No need .... save the suitcase space for other things, they will give you plenty of towels at the towel cabana's where you just show your room key to get a pool use wristband and towels. Plus, then they do all the laundry. They do sell Aulani beach towels which are really nice and a fun momento, but no need to bring your own towels.
As mentioned above just use the towel from the pool they are there for your use at the pool/beach, when done put them into the use towel slot... No need to pack extra You get the towels the same place you get your wrist band. Ensure you have your room key as they ask to see it and scan it before giving you your band.