J.G.
I haven't seen the movie, but try to get ideas from that. ie: party favors you could get some frog toys. Or I have seen Princess and Frog plastic cups(at Party City). Perhaps get each child a cup and just fill it with candies. Simple, quick, easy. Doubtful that the older boys would want a Princess and the Frog cup though. Maybe just find some frog cups or little sussies. There are a lot of frog things out there.
I like your lips on the frog idea.
My 3 yr old son is having his bday party next week. We're just having pizza, salad, and cake. I think my mom is going to bring some sort of appetizer too - deviled eggs, chips and dip of some sort. Simple simple. BTW - you can get cupcakes and stick frogs or rings or whatever else on top. That could be your small little party favor too, if you wanted.