How long probate takes to be granted, from date of aplication is pretty much pot luck ... having been through it twice in the last 4 years it really just depends on the size of any backlog at the time.
On the other question, I can give some insight..
With My dads will, a firm of solicitors were named as executors... and I was the only beneficiary. Thier fees were a little pricey and they said this to me:
I hope all of the above is clear however when we spoke initially I confirmed that we would not be obstructive if you decided you would rather deal with the probate application and the administration of the estate yourself and therefore if you wish to proceed along these lines, I will prepare the necessary deed of renunciation to renounce 'ourselves' as executors in your late father’s estate and the fee for preparing such documentation will be £500 plus VAT.
I opted to just let them handle it, as there were some hissy fits by other potential claiments against the estate, so in retrospect, it worked out for the best, even though thier final bill came to about 5k.
With my grandmothers estate, I am named executor, but I have taken on a different solicitor to do all the admin and final accounts, although I remain executor...they have said:
At this early stage in the matter I would estimate that if no unexpected difficulties arise it will cost between £4,000 and £4,500 plus VAT plus £273 and £1.50 per official copy and £2.00 plus VAT bankruptcy search for each beneficiary and £3.75 special delivery fee. This is just an estimate however and should the matter become more difficult than initially envisaged the estimate will be amended to cover the increased work.
Its not finalised yet but they say they are still on target with the initial estimated costs.
A lot really depends on the value of the estate... if the estate is several hundreds of thousands then 5k in legal fees might be a good idea to palm off the admin to a solicitor if you are finding it stressfull/ don't have time etc. it also provides a little layer of insurance, as if the solicitor cocks something up with the accounts or whatever, it's kind of on them, rather than you.
Basically, if solicitors are named as executors in the will, then they legally have to deal wth it. They can choose to renounce thier executorship, (usually only if you are the sole beneficiray, or by far the largest beneficiary), but they will charge a fee for that as they have to renounce thier responsibility legally, via some sort of court application.