Tent brands aside, were I in your shoes I'd be looking at 4-person tents. as others have mentioned, if you are the only adult you may not want to have any kids in a tent on their own until they are older. I have two boys, and a 4-person tent worked well for us, whether my wife was along or not.
If I were shopping now, I'd be looking hard at the Hogback - it is the lightest 4-person tent I know of.
As to what the kids will carry, I definitely believe in having them carry a pack, no matter how light. Mine started at 3 or 4 carrying just their pillows and stuffed animals. At 6 they were carrying their own sleeping bags, and at 8 they could carry all their own stuff - sleeping bag, clothes, miscellaneous. I just had to carry all the food, cooking stuff, and shelter. I find the tricky part is kids packs - most of them are too heavy.