I don't really like the idea of any of my assets being resold as assets somewhere else, because it's using my own stuff to directly compete with me (and potentially without putting in as much effort into creating them as I did - not gonna say you wouldn't), makes the copyright situation messy since the asset technically was created by multiple independent people, and a bunch of other reasons.... so I'd have to say no to this. (Having a derivative version of the engine available for free and as a fan project that could get into some IP law issues doesn't sound like a super tempting prospect either.)
Also, if you're planning to rework everything from scratch anyway, it might be less effort to try to make what you want from the start instead of retrofitting it into an engine that might not support it very well. I found a whole bunch of other tactics RPG stuff by just doing a Youtube search, so there's a bunch of it out there: