Hi OP
My DH and I have three children born by donor sperm. My DDs are 13 (quite mature)and my DS is 7. We have been open from the start.
We have talked about it a lot with all of them but no real issues or problems. Think one of my DDs likes having something different about her. I don't think the things you mention are likely to be issues once you actually start parenting. When you give birth to a baby, go through the 9 months, then years of sleepless nights, nappy changes, hospital visits etc parenting and love (at least for dh and I) becomes automatic.
There is no way my DH would walk on eggshells with our kids and ask me to be the disciplinarian. We both discipline them when necessary because we love them, in the same way that we give them lifts and look after them when they are sick. Sometimes kids say awful things to you (I can't recall the amount of times all 3 of mine have told me they hate me when I have stopped them doing something they want to do). They don't mean it, they say it because we are safe and they can. If they said "but you are not my real dad" which they might although haven't ever done, it would have very limited impact on us after all this time as we know they don't really feel that. They love and need both of us. If we divorced, which we won't, they would want to 50/50 with us because we are both essential to them.
Ditto my dh's family - they are just granny and grandpa who spoil them and given them lots of sweets. Both of my girls are exeptionally close with my dh's mum (not sure why she is a bit annoying from my perspective but they love her deeply and she loves them.) That isn't ever going to change and they always both talking about moving to where she lives in later life to be with her (over my dead body and I moving up there). They don't just feel related to my side of the family although like lots ofkids they like to talk abotu where they inherited certain traits from.
My kids were born just after anonymity ended so they can contact donor at 18. My gut feel is one will want to, the other won't and the little boy is too young to know. Neither my husband or I mind (genuinely, truely), our only concern is that they might get hurt and that is my only concern with the whole donor thing. You don't necessarily think about their feelings before they get here but once they do all you think about is protecting them. I hope these formative years with us and our openness on the donor issues will give them great resilience and confidence that they are loved and (different families are different etc) this will stand them in good stead if they do have questions but, of course, I don't know for sure yet.
Would DH and I do it again, selfishly, yes we would as they all bring us so much joy and I think they are happy kids who will add lots to the world. Join the donor conception network to get in contact with parents of older children and donor conceived kids themselves.