Group vs Person is not a big deal, its just a single json field thats named differently. The problem is that each software implements a slightly different subset of activitypub, because there are many different ways to do the same thing. So these incompatibilities need to be fixed.

The other day I noticed that Mastodon federates PeerTube channels as Groups that you can follow. On the Profile you can see this displayed as a ‘Group’ label (in the web interface). Don’t know how other microblogging apps handle this.