>low enough audio lag that geographically distant musicians can perform live with one another on the platform.
This seems like a pipe dream I think, since for low cost audio interfaces people can actually feel the few ms latency with those rigs going straight into their hardware. Anything going over the network has to go through an audio interface first, either with one of these dedicated rigs or the internal audio interface your computer uses for its built in microphone, then deal with network latency which will be significant in comparison I expect.
This seems like a pipe dream I think, since for low cost audio interfaces people can actually feel the few ms latency with those rigs going straight into their hardware. Anything going over the network has to go through an audio interface first, either with one of these dedicated rigs or the internal audio interface your computer uses for its built in microphone, then deal with network latency which will be significant in comparison I expect.