Hamster's a crepuscular which means most active when it's just getting dark in the evening and when it's just getting light in the morning, apparently they see best in this light. This means they're not the best pet for children as they won't want to be awake playing during the day, though you can train them to get up a bit earlier in the evening before your DD goes to bed. Definitely don't let yourself get talked into a pair of dwarfs, if they fight you're stuck with 2 cages.
Unless something's changed in the last couple of years you can't get hamster insurance anyway, putting some money aside is a good idea. Try joining a hamster keepers forum to get directed to a good breeder, you'll also be able to pick up lots of useful advice before you buy too.
Definitely don't get a rotastak cage, the only way a Syrian will fit through the tubes is if you get a really runty inbred one from a pet shop, please don't do that, and you can only get a 6 inch wheel in them. Show hamsters are on the scale of a baby guineapig, normal Syrians need at least an 8 inch wheel, I ended up needing a 10 inch one for my pedigree ball of fluff.
Your best bet with a cage is to get one big floor space, much easier to clean and more room for hammy to run about than one with lots of levels. Also with a cage on levels if the hamster becomes sick or a bit frail and elderly they get stuck on one level and suddenly have no space.
Anyway, I strongly recommend joining a forum. Hamster's are lovely pets, I plan to get another one once DD is a bit older.