Charging for Entry vs RMT

I want to make sure this topic is out there, so that we can get a clear answer to it.

I'm basing my questions off this: A streamer cannot host a giveaway on stream because it is considered RMT.

So these private leagues can have shared cost. What things CAN we do, and CAN'T we do, as streamers in regards to these private leagues?

Can a streamer host a private league that is only available to subscribers?

Can a streamer charge a $5 flat fee to all viewers who want to participate?

Anything else streamers should know before setting up models for these private leagues?

Anyone can choose anyone else to be allowed in. In fact now that I think about it I dunno if we even know, if it’s possible to Restrict anyone from Not joining once it’s been created. I’m assuming if you help pay you’re automatically in.

People can pay for coins to join. But paying them directly for ability to join seems sketchy