Remote-only companies existed before, during, and continue existing after COVID. And those companies have new people as well. Perhaps you're right and that it's harder to ask questions on slack as a newbie (although I believe it's completely up to personal taste) but is that worth all the benefits of remote work?
I believe it's not.
Eh, it's his code, his work. I believe he's within his rights to decide how he's compensated.
I personally think this method is a bad idea but then again I don't pay this game and don't even know what the mod does. Maybe it's the second coming or whatever and he knows his business more than I though. Either way, it's his right.