I’ve stopped development of TW5-Firebase, and began working on a near complete rewrite which is pretty usable at this point (I’m currently using it for a family wiki sharing recipes and trip photos).
I’d be happy to set up an instance for you which you could try with your friends free of charge. Everybody wins: you get a multiuser tiddlywiki, I get beta testers . If you’re interested, you can reach me at neumark dot peter at gmail dot com.
I am not sure about the consequences of no port forwarding, but bob and bob.exe are good for simultaneous users on the local network, however I am not sure if it up to date. There are authentication options in bob and node but I am not familiar with them.
It this is out of the question single file tiddlywikis can be multi-user over time, ie allow serial editors, a way is needed to ensure one editor at a time; ie can checkout and save the wiki at one time.
SharePoint if available can handle the checkin and out process for you.
Perhaps there is a way to use a subset of sharepoint in the cloud?
I’d love to give you access to a sandbox instance you can try out.
Write me an email at neumark dot peter at gmail dot com and I’ll add you as a user.
The current iteration (which I’m calling tiddlybase) requires no custom backend functions.
It uses firebase firestore db for storing tiddlers.