If I was the singer, (I'm not) I'd like a courtesy call before you made any money out of it.

If I was doing what you are, -and I am, but in a very small way,- I'd supply a copy to the artist as a matter of courtesy. An offer to his family, if he/she's gone, particularly for someone who achieved fame.

I'd separate the songs into individual files. This is a LOT more trouble to do than just digitising a session, but then you can cut out (or add in) whatever you want. Easier to do tape-to-computer than later, I think.

If I was doing what you are, in the big way, I'd keep a diary record of my hours and costs. Any moans, I'd ask for a pro-rata contribution.

Good for you, anyway, Bob.