I was the only one who could create communities on them.

Typically the only one who can create magazines/communities are local users of the instance. With registration closed, that means only you (or the new instance owner) would be able to do this.

Though one can get around this with some bot magic ( lemmit.online had a magazine that was dedicated to new sub/magazine requests - once someone made the request, the bot would create and own the magazine but add the requestor as the moderator )

Do you intend to have open magazine creation on these instances or would that still be restricted to the owners of the consortium?