There was a summoning script on a Side View Battle based around FFX. The best possible place for you to find the scripts you need would be rmxp.org. Also the resources. And you can make your main fighter less powerful by going into the database and messing with the Str etc. There have been a few pokemon games made with the RMXP though, So it is possible.

http://www.youtube.com/user/GhostlyFighterXx