You're not being unreasonable. As you said, plenty of people do PhDs while raising small children. I have no idea how some of them afford it or can move about Europe every few years with a wife and toddlers but they manage it.
The issue is whether or not you can manage the dual workload. Unfortunately your supervisor is the one who signs off on any paperwork which says you are or aren't meeting necessary targets. However, if you are clearly coping with the workload of both responsibilities then you really shouldn't have a problem.
I'm surprised you're held to a 9-5 thing. When I did mine people turned up when they wanted, left when they wanted, all that mattered was producing the result you were asked to work on by some fairly generous time. Hell, one guy lived on London with his girlfriend while doing a PhD in Southampton. I think he spent less than 6 hours in the department per term. Personally I always worked something like 2pm to 8pm, including weekends. As for my supervisor, well she was awful. I'm certain she didn't read my PhD before I submitted it, despite being asked to, she didn't know the answer to basic, relevant questions. Not a single word or equation in my thesis had anything to do with her. Fortunately I managed to develop a good work ethic by myself, which now serves me well in my job where I'm pretty self motivating and directing. My supervisor's other student wasn't so lucky. She (the student) asked to take on another supervisor and the supervisor said "No, it's your fault you're doing badly, not mine". That escalated to a meeting with the head of department, who said "Take a second supervisor but on your head be it".
If you feel you can produce the work and you can demonstrate that during the last few months while juggling both you have maintained a sufficient level of work then make it clear to your supervisor that if necessary you'll go over his head to speak to someone. It is not unreasonable to time shift your work during a PhD, everyone has responsibilities for various things. If your supervisor still has a rod up his backside then, if you think you can do it, go it alone or change supervisor. Unless you're spectacularly lucky and have a supervisor who does active work with you, rather than just giving you tasks to do on your own, you'll be fine. By now you should have an idea what area you want to do your thesis on anyway.
Perhaps you found that you were pushed to the extreme by your PhD, assuming you have a PhD (I don't know, I don't pay enough attention here) but that isn't really true. Like I said, I knew people who never turned up to the office and did work when they pleased. I personally liked to work afternoon/evening but I know people who work 7am to 2pm, leaving the evening open to do with as they please. My area was mathematics and theoretical physics and some of the greatest researchers in those areas famously only worked 2 or 3 hours a day for their research. If someone works in a lab then there's a certain amount of grind which must be done but sorry, your blanket statement is just not universally valid.
I wouldn't agree there. If the OP can demonstrate he has been able to juggle both without compromising his work then it isn't unreasonable to stand his ground or go over his supervisor's head. A reasonable head of department wouldn't just dismiss him out of hand.
While I don't deny that people live and breath their research when doing their PhD and often go through weeks, even months, of pulling 12+ hour days it isn't necessarily to the exclusion of all else. In fact, I would say that if you spent 3+ years doing work every waking second (aside from visits to the bathroom and eating) you have the wrong work/relaxation balance. I worked 8 hour stints every day for 4 months to write up my 350 page thesis, without any assistance from my supervisor and with no collaborators. I still had time to visit my girlfriend 200 miles away regularly and had every morning free to do with as I pleased.
Yes, if someone is thinking of starting a PhD they have to be prepared to spend extended periods of time doing nothing but their research day after day, but it isn't for the entire time of the PhD. Regardless of how much someone might love their work, that simply isn't healthy and it isn't the reality of most people's PhD. I don't know if you had a particularly harrowing PhD or you have some desire to make it sound like the 12 trials of Hercules but you're not giving a very level description of the typical PhD.
It might be reasonable to expect a 9-5 office time from a researcher but unless there's exceptional circumstances a supervisor cannot force you to do those times on a regular basis. Yes, some people do meet their supervisors at weird times or at their houses or even for a meal but I'm pretty sure there's basic laws which prevent what you're describing from being enforceable. European laws about maximum work hours per week for instance. Yes, people might decide to work more, if they need to, but you cannot be forced to do that sort of thing, especially if you're able to demonstrate sufficient research during normal hours.
You're describing individual idiosyncracies of people's supervisors, determined by mutual willingness and personal quirks. Only a supervisor with a clear personality disorder would report you for incompetence or insufficient work because you don't go to their house at 10pm on a Sunday, provided you're clearly meeting reasonable work hours and producing work. Yes, if you refuse to speak to your supervisor then there's an issue but if you say "I'm in the office 7 hours a day, every weekday, and often at weekends and I'm available at reasonable hours for meetings" (and you can prove it) then they cannot call you on it. People work funny hours during PhDs because they are willing to and generally there's a level of mutual willingness from supervisor and supervisee. If the issue were forced and someone didn't want to go to their supervisor's house at 10pm on a Sunday there isn't going to be grounds for dismissal. A supervisor who takes on students and who then makes themselves unavailable is in the wrong, not the student. If a professor knows they will be away for months at a time then they should not take on a student or they should make it very clear from the start and offer an interim supervisor or sort something out both parties agree on. My supervisor got pregnant end of my 1st year and buggered off for 6 months of my second year. I had to ask for a second supervisor, the other student put in an official complaint. Do you think my supervisor would have had a leg to stand on if she'd complained I hadn't seen her for 6 months, when I was in the office every day and she was at home with a baby? No bloody way.
I think your advice is terrible. You're painting a PhD as some trial through hell. Yes, at times it can be, at times you have to do 14 hour days with no help and no guidance, but that's only for small periods of time. A few months at most. It isn't the 3 years of having your fingernails pulled out you seem to be trying to paint it.
If the research is good, the department is made aware of any grievances, work commitments are met and everything is done by the book then you can just say "F U" to your supervisor if needs be. It's not advisable and it will make getting a postdoc place harder if you don't have mindblowingly awesome research with loads of citations, but if you've got the balls you can do it.
Personally I barely spoke to my supervisor the last year of my PhD. I didn't go to see her when I got my PhD awarded. I don't keep in touch. I have no idea what she does now, she is no longer part of the faculty and I wouldn't be surprised in the slightest if it's because she did bugger all for 4 years. It made for a very stressful few months but coming out the other side of it I certainly think I have a better work ethic and self motivation than I had going into the PhD. I might not wish it on anyone else but being ultra chummy with your supervisor isn't essential. The relationship between her and the other student was even worse. That went to official grievances. But the student stood her ground and got the PhD in the end. Not as good as she might have done but she didn't throw away the 4 years.
A supervisor doesn't have to be in your viva, many decide not to be. Even if they do sit in, they cannot chip in and help you beyond the most basic of things and even that is considered quite out of order. There's generally someone from the department there, the internal examiner but quite often they aren't familiar with your specific area and so defer to the external, who is supposed to be the expert on the thesis topic. Like I said, I didn't get ANY help from my supervisor. Not a single word, equation, suggestion, idea, anything, in my thesis came from her. She was worse than useless for me, because I expected some help, she made initial motions to seem like she would help but then sat on her arse. I wrote a 70 page paper single handed and got it accepted by a reputable journal. I remember telling her I got it published, after I'd given a 45 minute presentation on it to the department (part of our duties as postgrads), where one professor had expressed loudly his surprise I'd done it single handed. I didn't even mention her in the conclusions, though I mentioned a few other people. Her expression made the whole 4 months of working by myself worth it, just to stick it to her. Unfortunately the other student wasn't so lucky, they'd co-authored a paper and then the supervisor dragged her heels. The student couldn't publish it by herself, it would be a violation of ethics to do it without all authors' permissions.
So if you can produce the work, can demonstrate it to the department, are willing to go the nuclear option of telling your supervisor to take a hike, you can do a PhD by yourself. It's not to be recommended but it can be done.
Well I can tell you from personal experience you're wrong.