This is an excellent list of solutions. I love the multiprong approach.

I love this idea. I've had unban requests that are really just sent as a means of harassing me, the streamer, further. Putting up a paywall to do that, even if it doesn't slow people down would at least compensate me for my time.

I honestly already thought this was a feature of teams since I see so many of the same mods in the chats of members of the same team. Why isn't it?

Adding a Captcha to account creation would be a good step toward combating the prevalence of hate raids and view bots on the platform. Having a Captcha at account creation might also give Twitch more options when it comes to removing the bad actors who are the actual people behind these actions, as they would be actively subverting a site safety feature.