are indeed related, but not necessarily that way.
Beelzebub - originally Ba'al-zvuv ("lord of flies").
Ba'al (meaning "lord" or "owner") was a name of a canaanite god, and
Jezebel was a leader of the Ba'al followers.
But the "bel" in Jesebal is originally "vel", and the "beel" in "beelzebub" is "ba'al" - sounds and spelled differently, so I don't know.