We took our daughter to DL at 3 months, and then to WDW when she was 6 months.
I'd recommend getting an onsite hotel (or one of the ones across the street), because you *will* be going back to the hotel room for naps for your kids. You don't say whether you'll be breast or bottle feeding (perhaps it's something you don't know the answer to at the moment), and that will make some difference, since the breastfeeding means *you* have to be around to feed them.
Also, check with your family to see how much help they're willing to be with the kids. When we went to WDW with our daughter, we took 2 grandparents, 2 aunts and an uncle. All of them said they'd help look after the baby, and most days we were the ones stuck going back to the hotel room to make sure she got her nap. We did get *some* time off, but very little (and much less than we expected).
That all being said, as long as you go in with realistic (and pretty low) expectations about how much you'll be able to do, you should have a good time. You can go on all the dark rides with the babies, visit characters (depending on their personalitites, ours was fine with 'em), watch the people, swim if it's warm enough, visit with your family, etc.
Enjoy your babies once they arrive & good luck making the decision about whether or not to go to DL.