Cleaners won't eat bristleworms. Like El Guappo said, they are liking hiding during the day. I also find that bristleworms are adventurous when there are no tank inhabitants, but once you put a few other critters in there they hide all the time.
Be aware that Margarita snails are a temperate species, and putting them into our tropical tanks increases their metabolism which makes them great algae eaters, but it also greatly reduces their natural lifespan. Something to be aware of if you are humane conscious (for lack of better description).
Astrea snails are great additions, and are very hardy. Stomatellas are my favourite. If you ever decide you want to get a Peppermint shrimp he will likely eat all your Stomatellas (but no other snails).
You're right, there is no need to feed your Cleaner shrimp. You have enough live rock for him to pick at.
