What is the best facebook fediverse platform. I want something that is more private which you connect with friends and family.

I know of Frendica and there is Minds which is not yet federated but is working on becoming federated.

Could lemmy be used as a private self hosted forum?

And could lemmy be used as a private forum were only registered users and whitelisted users can view, post and comment on the instance. This way you can have a private instance which only paid users of your group or club can join like many membership website forums have.

XMPP is lighter than Matrix. Both are better than Discord. Tell your friends to switch

Ball a rollin