Anything you post on the internet is public and you should stand behind it. If you want to be anonymous on the fediverse there's steps you can take to make sure you aren't easily doxed. use a unique username and email thats not used anywhere else. don't post photos that can possibly be geo located. Don't mention who you work for, don't mention places you visit. Pretty basic stuff.

Metas new Twitter competitor Threads claims it will connect to the fediverse eventually, it doesn't yet. If Threads does then I expect he'll use the old microsoft "embrace, extend, extinguish" tactic. Add extensions to ActivityPub that only the the threads client and server support in the hope that Threads client becomes the dominant way to access the fediverse then when all the clients give up, he can drop support for it.

I meant from a users point of view? is there a way to combine our usage of lemmy / kbin and mastodon?

Technically you can view & interact with kbin & Lemmy from Mastodon and vice versa? - As a user or you mean if I wrote code to do this?