Shabbat and Mila

Question

Dear Rabbi, Three unrelated questions: 1) Twin boys are born, both premies, and cannot have their milah in time. One subsequently becomes ready before the other one. It may be a financial burden for the parents to have two britot (I'm not sure), but they are willing to do so if necessary. Can they delay the first baby's brit until the second one is ready, or must they perform the mitzva ASAP? 2) Is one permitted to give a gift of food, such as wine or cake, on Shabbat? I am assuming that no hotzaah or use of eruv would be involved - let's say the two parties live in the same building and have a proper eruv hatzeirot. 3)Follow up to a previous question: Although I understand that saying haGAfen is not necessary because we don't observe such technicalities of Biblical hebrew in everyday speech, I was under the impression that there is a real grammatical difference between nihiyEh and nihiyAh. The Acharonim speak at length about this, although that doesn't necessarily mean anything. Is there any halakhic difference between the two ways of saying the beracha, or is it just a matter of minhag?