I don't think both will be long term pieces on this team, so yeah, I don't see losing the less of the two as a big deal, though I don't see Guenette getting claimed. He doesn't have the track record or the draft pedigree for me to be worried about it.
But in the event both are significantly better and we are actually worried about losing one, we run with 8 D, and rotate in JBD and Guenette, maybe look for a trade that makes sense.
Just leave some cap space to allow for callups and we're fine, worst case, use the emergency callup provisions like we did this year.