@JonasJRichter @FediTips yes and yes. This all makes sense. To interact with specific comments you'd have to grab the direct links to those comments and search them on your instance. That should "pull" the comments to your instance.
To post to a Lemmy community you make a post with the first line as the title followed by a line break, then the content of the post, and another line break, and mentioning the community.
Comments work similarly, for it to show in the community, the user and the community should be mentioned.
The way mastodon shows content from other software is specific to mastodon. They don't exactly comply with the standard. Mastodon only accepts "note" activity types, while these other softwares like Lemmy and Mbin use the "article" type if my memory is correct. If they'd allow article type content, posts might show a lot better within mastodon directly.😬🤷♂️
I hope this helps and all makes sense. I'm not FediHelp but I like to help Fedi, so I figured I'd try.😅