bigace's script is the one that is going to need to be made compatible. While it is a bestiary system, the fact that you can do test battles requires his script to make edits to the battle system. So, as of right now, his script only works with the default battle system and perhaps some add-ons, not completely new battle systems.
I've taken a look at the script and I noticed that a LOT of the code can actually be aliased rather than rewritten, allowing for his script to be compatible with just about any battle system. If he's not willing to do it, I can probably take a crack at it on my free time, but that won't be until a few weeks.