Hi Adrian,
I absolutely think it’s a good idea to have a core team to share the load so that everyone can have fun with the project without any single person having to feel inundated with a deluge of maintenance tasks.
I’m more than happy to help out in whatever form the core team takes. My involvement might be a bit bursty, based on experience finding time to maintain packages in Debian, but I’ll do my best to keep up a a more sustained presence here. I don’t think that will be difficult given the efforts you’ve put in to make the community welcoming 
On practical matters I think a communication channel would be a great starting point, whether it’s a separate area here on discourse or something more like IRC or its more modern equivalents.
Cheers,
Carl