[Other] How can I customize ROM mods that aren't mine?

Now I want to play Pokemon Wonderguard (Emerald) but I want to run this rom mod without the randomizer. I want to keep the existing feature where all opposing pokemon have wonderguard, but I want to make it a semi-normal playthrough. Is there anything I can do to remove this moveset randomizer? If so, is it easy to edit?

It may not be possible, depending on how the maker of Pokemon Wonderguard randomized it.