I've been using MoinMoin for many many years and just got hit with it not working for python3 wsgi.

Right, moin 1.9.x and also unreleased "moin2" still require py27.

I'd like to find out what your plans are beyond the Wiki and how I might help.

Best help is getting involved in moin2 development and working on issues, but not porting to py3 right now. There are quite a lot of more pressing things to do than the py3 port and the py3 port might even rather get in the way / slow down these things (and also delaying the release of moin2). See the github issue tracker for stuff to do: https://github.com/moinwiki/moin