Unfortunately Reliability, it doesn't quite work that way. At least I don't think so.

As far as I'm aware, RPG Maker uses animation sprite sheets and you use the RPG Maker interface to do it frame by frame. It is sort of like how Flash works but less versatile, if you want a variety of sprites in the animation then you'll have to create a new sprite sheet with all the sprites you need on it.

After Elite 4 should be Olivine and Cianwood City, one of which will have a Gym Leader you challenge for Blitzfaust/Vilephist, and one with a vaguely discussed Ampharos Lighthouse sidequest which has not really been fleshed out yet. Also, Soma Island will be available as a simple extra island with some puzzles, items and rare Pokemon, and later on the Windshear, Sunshine and Rainfall (don't remember if those were the names) Caverns will be patched in with the RSE Ubers and various Pokemon of their typing. That's all I can think of at the moment.