I think they can only "reasonably" (or legally within the settlement) sue people distributing it that are in talks with the original Yuzu devs. Again, I'm no lawyer, but this is what I got after reading the settlement and reading about it online and stuff.
Of course, they probably could go after...
Yuzu didn't lose, it was settled out of court. No one won technically. Also, the settlement stated that the only ppl that were not allowed to use the source code were people that were trying to collaborate with the Yuzu lead devs (AKA, the ppl that got sued)
ETA: I'm no lawyer. These are just...
Correct me if I'm wrong, but as far as I can tell, it doesn't seem like it's Nintendo that gave them the DCMA takedown notice. In fact, it seems implied that it was actually Gitlab themselves that gave them the takedown notice for reasons probably very similar to why Steam removed Dolphin; so...
I feel Citra at least is less of a target though, since the lawsuit was focused on Yuzu. Citra shutting down was more so an added bonus for Nintendo since they could kill 2 bird with one stone. Hence why I think an actively developed Citra fork is more likely than an actively developed Yuzu fork
Caller -"Everytime I start a Pc game on my S24, playing on a external monitor, someone calls or texts me, n it kicks me out of the game." Customer Support - Click (hangs up)