You'd better off just getting the Ubiquiti AmpliFi HD router. It looks good sitting on a table too.
I'm going to disagree on that one. If the AP-AC-xx is mounted on a ceiling, high up in the building with a good ground plane then it will do a significantly better job than the Amplifi product. And an AP-AC-LR is £100 compared to the Amplifi products at several times that.
I think the original suggested solution is excellent. There is a thread on the Unifi forums where an experienced installer suggests never having more than 1 Wall or Floor between a user and an AP. I used that rule and I have 4 APs in use in my own home/office and the coverage is excellent, as you would expect. The best bit is when I change something it is instantly rolled out to all the APs simultaneously. No messing about.