Yellow tail are around in Dec, its actually a very good time for them, BUT CB is not a known hotspot for them. Mbolompo is the go to spot, or Brazen head. Both a little way away from Coffee Bay. Mapuzi Pt may hold 1 or 2, as will Black Rock, Hlunguwana and The Queen but Mboloimpo is def where you want to be.
You are probably under gunned for the tail there, they are quite big on the whole, 8-20kg size, not too many of the little guys. Unfortunately Mbolompo is being over run by the drone brigrade, and not a place to fish alone, especially if you are new to the area.
Spinning wize, thuough, weather dependent, fishing Umatata mouth you could get kob, leerie and Kingies, YT, Big eye and GT. These will also be around most of the beaches, and points.
I havnt fished CB itself, other than from the sea, but the points within a short walk/ drive of CB worth a shot. Gert a decent gillie though, often the rentasl house/ hotel/ back packers can assit, as you also need a car guard when fishing the remote spots. Unfortunately its a poor area, and too many will take a chance.
I will aslo be there over dec, but

are the target.