A: You will probably have to order the annual passes one or two at a time. You can only use 2 gift cards per purchase online. I ended up calling, and it was the same thing. Had to break up the purchase to order all of our passes.
A: Yes you can, we used gift cards to purchase ours. Just takes forever to type all the numbers in LOL
A: Yes you can do that.
A: Yes you can, you can use the gift card just like a credit card
A: Yes you can, but you must do it via Disney's website that merges gift cards.
A: Yes, you can! Literally, a Disney Gift Card can be used toward anything officially owned/operated by Disney - so if you do it on the actual website, it'll work!
A: It should generate it as a barcode, where then the Cast Members will scan it!
A: Yes and yes. I just double checked by trying to purchase one to see if the 5% discount is there and it is.