@hedge Right now, most Fediverse projects are analogies of their centralized counterparts, albeit with some differences (e.g. you can add a title to Friendica posts, but not on the Facebook ones. You can add inline media to Friendica posts and comments, on Facebook you can't etc.), so you can take that in a way. A short answer to your question would be the one in the first comment of the post:
Interaction between Lemmy and Mastodon doesn’t work well because the two services structure their content differently. Lemmy is community based and Mastodon is user based. Lemmy doesn’t have a mechanism to follow an individual user, and Mastodon doesn’t have an analog to communities (afaik).
With the addition that you can follow Fediverse groups on Mastodon, but you cannot create Fediverse groups on Mastodon (as Mastodon itself doesn't have any group feature). If you're not looking into creating and admining groups yourself, then you can safely consider Mastodon. Otherwise, you can pick Friendica, Kbin, Mbin or Hubzilla (among others). In fact, this is how I see this very post on Friendica.