Kun's double-bladed saber appeared a few years before Maul's, although i'm not sure if it inspired it (as Lucasfilm occasionally was inspired by elements from the EU, in particular the artwork-hence comic character Aayla Secura showing up in the prequels) or it just happened to be a sort of convergent concept.

Exar Kun almost made it into Disney canon, Solo would've had Vos's desk made from part of his temple. I think however, Disney slightly altered the canon of the Yavin Temple's past (originally they were Sith temples built by early Sith Lord Naga Sadow but later refurbished by Kun) with Doctor Aphra's first arc but I'm not 100% sure about that.