Like Holly, I deal with Lactose Intolerance. I can't get myself to give up the dairy, so I just live on Lactaid.

Although, I imagine you can't do that with your daughter. I find acidophilus (you can get acidophilus milk) and yogurt help. In addition to the lactose free formula, there's lactaid milk. There's lactose free ice cream,

. I'm sure that would help a fussy eater, although probably not make for a great mom. They also sell goat's milk, which some people with lactose intolerance are supposed to tolerate better. Cinnamon also helps. I have no idea if you can give that stuff to a 16 month old.
Also, I wouldn't worry so much about filling her up with solids. Is there lactose free formula or lactose free milk you can fill her up with before bed? I agree too w/Holly, that I found my daughter wasn't really hungry at night. She just wanted the comforting and I had to wean her off of that. But, I think a mother usually knows what is really going on. So, if you think it's hunger, you're probably right.
My daughter also has had a lot of gas and I've found that sometimes it's actually teething. Apparently the drool can get in their stomach and cause tummy troubles. I use those homeopathic teething tablets and they work well. I feel for you, twins! You must be about to keel over.