Zardnaar
Legend
I am pretty sure he was the first guy to be frozen in carbonite with the machine Lando had. It didn't sound like it was supposed to be used for that. Wether freezing people in carbonite was never done before I don't know. But I kinda doubt it was something commonly done.
It's not something that was done that often in Legends. In the RPGs it was suggested as a way to use ancient Sith in the modern era.
Morrus in the old legends Fett survived the Sarlacc. In the new stuff they've refused to confirm Fett's dead and his movie probably turned into the Mandalorian show.
Mandalorians haven't changed that much between the old 90s depictions and the new. They could fight Jedi and generally lost to Masters. The only real difference was culture on Mandalore when they were used in The Clone Wars. And they kind if retconned that in Rebels.
They're more or less space Spartans.