Oh god..Yes they did.
Not only did nobody you thought you had killed in the first come back, It was almost like you had done NOTHING!!! When I saw ursula was back [and oogie, and jafar, and maleficent] I was like "HAS A STOP SPELL GONE HORRIBLY WRONG OR SOMETHING?!!" i killed them again and if they come back, i will bite my tongue off.[not really but you get the point]