Not really the perfect answer, but it probably helps you. Fedilab support Mastodon and Friendica account, but not lemmy account, so maybe that’s a problem for you. But you able to follow besides lemmy communities, which is normal for mastodon, lemmy instances, so the local feed as well.

As i said, not the perfect answer, but if you are interrested take a loot at fedilab mastodon