Umm, why would you not be meleeing? It's extra DPS. Regardless of your weapon, you should be meleeing. With Yeb-Soth's, even more reason to do so.
Overking = Sure
Venril = Only when Sanctuary is up.
Kluzen = Yup
Nexona = Yup
Ekron = Yup
Druushk = Also Check.
Taskmaster =

Milyex =

Xygoz = Yup
Qunard = Yup
Hoshkar = Yup.
Travenro = Hmm, probably not.
Silvering = DEFINITELY Yes.
Phara'dar = I'd say Yes too.