The sprites could easily be fixed. I just added this feature to my game, which is still a WIP and has no playable demo. It wouldn't be that hard to script if you follow this tutorial:
http://www.pokecommunity.com/showthread.php?t=316403
Also, the sprites could easily be found at spriters resource or other game developer art websites like Deviantart, etc. HOWEVER, people have uncovered that there was code and sprites for the gen 5 pokemon as well. They have been recovered from the game, and can be found in the Ultimate BW Pack 7 for Pokémon Essentials, which is what Reborn is made in. The following people behind you thing works with the following pokemon too. The only thing is acts like a caterpillar. You have the player then the pokemon then the partner. My reccomendation, whcih is what I have done in my game, is to have the partner get you to checkpoints, and heal you up, but he doesn't walk with you. He runs ahead marking the way to go.
Well, I repeat again. It's easily possible to tweak the scripts slightly to have pokemon following you.
Best
Pokégod7020(pokécommunity)/Allgamesdude(Deviantart and Here and a lot of other places too )
