Lets see....
If your DS is into Mr Potato head....they a Mr Potato set you can buy at DCA. You get the box and get to fill it with the accessories you want. They have some CUTE options!!!!!!! Mouse ears and mouse shaped ice cream on a stick. SO adorable!
The animation building is great. 2YO will probably love the lobby (they show bits of movies on large screens, lots of music and 'dancing' light show on the floor). The MuShu show is interesting. I'm sure your 8YO would like it, 2YO may or may not. then there is the 'hands on' stuff. My kids always like that.
2YO will enjoy Playhouse disney. They often have Playhouse characters outside the attraction.
2yo- there is a bug show, I think it's called the ugly bug ball, it's right outside of flicks fun fair and is very fun.
Flicks fun fair there is flicks fliers which both kids should enjoy, the catapiller (train) 2YO will love. There is a bumper car ride...don't let 2YO see it! You have to be 42" I think....I hate that it's in a primarily little kid area...anways, 8YO would probably enjoy that. And then there are the water fountain things, always fun.
My kids LOVE the boudin bakery tour! They'll sit through the whole thing, and then want to do it again. The tortilla tour is short, but my 5YO LOVES the little movie at the start. It's kids doing an 'oral report' and she thinks they are just too clever.
Both kids should enjoy the ferris wheel. Depending on the height of 8YO, she may be able to ride some of the other pier rides too. Mullhuland madness is fun, and my 5YO likes jumpin jellyfish...not sure if it's to 'babyish' for an 8YO.
The only other MUST see I can think of for the whole family, the Redwood creek trails. Hopefully mom and dad are in good shape so that you can keep up with the kids
There are a few 'attractions' that only 8YO can do, but for the most part it's just a fun family place to explore and sometimes interact with characters (Big Brother) too!