“So according to Kalei Hapsak, the Halacha would be that dancing and singing is forbidden even for Ashkenazim.”
Why do you say “even?” We do posken it’s assur.
“Answer: I still think that our Maalos outweigh our one or two “Limmudei Zchus”.”
Like what? All of Chabad’s unique minhagim are extreme kulos. The chumras are just standard Chassidishe practices done by other groups that don’t also have the kulos.