I can't help with some of your questions but just wanted to say that I am A negative, had the Anti-d jabs and had 3 healthy babies who are now grown up. OH is O positive. Not sure what they do these days but I just had some extra blood tests during the pregnancies to check I wasn't producing antibodies. Please try not to worry!
Please don't worry. I have 2 healthey DDs and I am rhesus negative. My DD2 is now 10 but when she was born I had Anti-D after birth and that was it! No extra checks or anything, although things may have changed now. Be reassured that everything was fine with no pre natal intervention in my case.
I would make an apointment to see your midwifa and explain your concerns, I am sure she will reassure you.