Hi ER - just read your response in the other thread, it sounds like you're doing great, such a shame about 7year but I bet she enjoys being the grown up and reading to the little ones!
I know this might not sound like much fun out loud, but I found my neice and little cousins around the same age loved being able to help with housework. I would squirt furniture polish on the furniture and hand one a duster, the other one would sort washing into piles, anothjer would dry spoons bowls, etc/ Admittedly sounds a bit crap, but they'd have so much fun thinking they were helping (usually making more mess than anything else LOL) and playing some music they like too :-)
What about making pizzas / decorating cakes?