Hi, merry Xmas!
I'm really happy you find PuzzleGraph useful to use for your teaching.
PuzzleGraph is open source, and you're welcome to make a clone of the repository and add features there. I'd follow that with interest! If I end up liking them, I can roll them into the original distribution, and either way you can distribute your version yourself. The source code repository is here (in Mercurial format):
https://hg.sr.ht/~runevision/puzzlegraph
Cheers!