I am actually heading there next week. Playa del coco. The hotel I am staying at has free kayak rentals
I am in the same boat as you in regards to gear, I plan on stuffing two rods in my surfboard bag and bringing two reels and a handful of cranks/jigs/swimbaits. I have no idea what those fish bite haha. If you youtube fishing in costa rica you can see shore-fisherman catching Jack crevalle from shore.
I will try and remember to PM you when I get back! I leave Friday.