I like all Ludo's army members and i think all of them are alive. For example, in On the job, like Buff Frog, one of the other monsters survived, the unnamed fly monster (who now goes by the name Boo fly) survived two, when Buff Frog was talking with him on the phone, Boo fly mentioned that the explosion almost kill them all what could mean all of them are still alive, but when will they appear again in future episodes is for now stated unknown. I hope all of them survived.