On the one hand, it's a nice bit of foreshadowing that something deeper is going to come of this part of the story. OTOH, this is a story has already exploded from a family curse and a lich into saving literally all of existence, battling the gods, facing an unknown triad of evil superpowers, multiple genocides, at least one illegitimate child and one wedding, and killing the mother of all dragons. Kinda makes this plot feel like icing on a cake that's already mostly icing.
Redcloak might not be as hard to convince as Roy and Durkon think. Remember that he had a fake phylactery for Xykon created way back. Chekov's phylactery will come into play, and it's not going to be for Xykon's benefit, so I believe Redcloak understands Xykon does not have goblinkind's best interests at heart (or empty ribcage).