I've been to Cayo Coco twice. Stayed both times at the Melia Cayo Coco...which is billed as a 5 star resort, but keep in mind a 5 star in Cuba is a 3 star (at most) anywhere else. Beautiful beaches, and the flats fishing for Bonefish, Permit, juvenile Tarpon was fantastic.
I went out with Mikel Ceballos...you can find him on Facebook. Great guy, personable, funny and one of the hardest working guides I've fished with. Gets more excited about catching fish than his clients. Last time I was there, the Cuban gov't was in the process of eliminating private independent fishing guides. They want them all to work for "Avalon Fishing" which is a gov't agency...since it's a cash business, I imagine the idea is to make sure the gov't gets their cut. Not sure what the current situation is with Mikel, but reach out and see if you can make arrangements directly with him.
There is good DIY fishing on a flat a short walk to the east down the beach from the resort. Wet wading and sight fishing for Bones. Bring your own gear...a medium spinning outfit will cover most situations for Bonefish (maybe something heavier for Barracuda and juvie Tarpon)..get a 3 pc travel rod that you can stash in your luggage. Grab some Bonefish jigs...I get them on-line from Buggs Fishing. 1/8 to 1/4 oz jigs with twistertail plastics work too.
Anyway, unfortunately I won't be returning to Cuba again unless the gov't changes. It's an absolutely beautiful country with super friendly people, but their system of gov't is running it into the ground. There are constant shortages of everyday products, regular power outages, and frankly most of the food at the resorts is sub-par. Last trip there, they were rationing toilet paper and bottled water at the hotel...
Yeah, Cuba is a lot less expensive of a destination than other spots in the Caribbean, and the rum and cigars can't be beat, but if I'm on vacation, I don't want to have to worry what I'm going to wipe my a$$ with...
Bahamas, Mexico, and Belize (my favourite) all have great fishing, and they aren't third world communist dumpster fires....
Bring big poppers and wire leaders for the Cuda..