Make an IC channel in a discord server for roleplaying purposes, where people can chat IC in a setting previously agreed on, then paste the whole thing in an RP message and post in game? It doesn't address any of the issues I would want to fix with IC chat, but, still seems slightly borderline so I thought I'd ask.
I encourage this sort of thing. It makes roleplays with multiple people much smoother than the slow and disjointed way they happen in-game, while still having the whole thing entirely in-character and entirely accessible to everyone in the realm (once it's posted in an in-game message). I've done this many times over IRC (many years ago, sadly).
As for the rest, I am still very firm on the in-game message system remaining the
only form of in-character communication.