Your question about “what is reasonable to ask from donors”.
There are many questions you need to ask all prospective donors:
1) What is the contents of his sperm like =the DNA? Sperm banks issue donors with a genetic check list to eliminate problem genes in his ancestors, siblings, close family like cousins and decendants. If he has kids can you see photos and talk to the mothers. I try and link the applicants with satisfied mums so they know what my genes look like.
2) Do his sperm deliver the DNA? Will his DNA carriers do their job and find&ferterlise your egg? Successful donors are one avenue and virgin donors should show a Sperm analysis (Volume, Number/ml, Morphology and Motility).
3) Only sperm and no NASTIES? (HIV, Syph, Gon, Hep & Clamydia to name the worst). I am a regular blood (Plasma) donor so the Red Cross test me fortnightly for STDs. He should be able to show you a recent STD result. Time frame is not so critical for AI donors but for NI donors it is a must.
4) His relationship with you and your kids? Do you want to A) co-parent and share the costs and the wear and maintain your career or perhaps have 4 kids with his contribution. B) Known Donor where he is known to your kids and has an uncle/grandfather role in their lives (essential if you and your partner want more than one child with the same DNA. C) Unknown donor if you want to fuck your kids lives up.
5) Consanguinity? Do you want your daughters not to marry their brothers. If you only have one or two children and your donor has 20+ other kids do you want your kids to know and to have a relationship with their 1/2 siblings? Some women don’t want “Serial donors” but virgins. If so marry them or co-parento them. But you have NO right to deny him what he is generously giving you for free. :D