Lilo's got a Dumbo plush sitting on/by her big drawing pad on her easel near her bedroom window... in Lilo & Stitch.

Plus, a lot of the control room aliens are otherworldly versions of Pooh and pals, near the beginning of the film after Stitch escapes.
Oh yeah! In 101 Dalmatians, during the Twilight Bark sequence, Lady, Tramp, Jock, Peg, & more dogs are seen pitching in. And I'm pretty sure that Pongo (& maybe more dogs from L&tT again) is glimpsed being walked in NYC in Oliver & Company while Dodger is singing "Why Should I Worry?".
