That's a great questions @noffle.

I intend to build it in Patchbay first, because it's an excellent prototyping space. I want to build it following the scuttle-pattern - as in helper modules which can be used anywhere, providing async methods and pull-streams.
If you've not seen my recent work with this pattern, I don't assume patchcore at all, and have been writing html components likewise (as in if a template needs to render avatars, you're expected to pass a fn in that does that)

I would love to see this accessible in all clients, but feel like gaurenteeing doodle-gatherings-routings total integration would take a lot of work across 3 clients. The good news is that each part of this is useful and renderable as a piece of that flow. e.g. if you can already see gatherings in your client, that part is done already.
One path could be to offer dedicated support (i.e. pairing, reviews) to core devs of any client interested in having this complete flow, along with some atomic components which can be forked and easily reworked.