Can AB ve marry AB ve?

if in donor blood antibodies against AB is very low, then he can.

yes

Yes, no problems there

Yes an No. You can have blood type AB in following situations: AO+ BO AA+BB AB+AB So there's more possible ways to get type AB other than the combination of ABs.

they did not have A and B group at all so they can only produce a baby with O -ve or +ve