Stitch & Buzz won't work for you. Neither has a height requirement and you're allowed to take babies on them so you can't get a rider swap pass. Your plan for 7 Dwarfs, Splash, Space and Thunder will work. We found it took a LOT of time even with the Rider Swap passes to actually ride the rides in this manner.
When we used Rider Swap in November they wouldn't give us the Rider Swap pass without showing a child that was too small to ride that ride. Happened three times (Everest, TT & Soarin'). We didn't try for Rider Swap on any other rides.
When we used Rider Swap in November they wouldn't give us the Rider Swap pass without showing a child that was too small to ride that ride. Happened three times (Everest, TT & Soarin'). We didn't try for Rider Swap on any other rides.