I believe that there is a literature related to donor gametes, but relates more to premature ovarian failure where the recipient can be expected to have some accelerated vascular aging - one donor gamete increases risk (whether egg or sperm) and two moreso. The surrogate mum was immunologically-naive to both parents of the pregnancy - and this was a dyad who had previously had a pregnancy complicated by pre-eclampsia. In terms of placental formation, this represents a number of hits.
As long as [the original poster] remains with the partner of her first pregnancy, I suspect that she will not be at increased risk for pre-eclampsia in a spontaneous pregnancy. Unless she has developed an intercurrent illness such as a vasculitis of which she is unaware.
I really don't know the answer to the third question.