calves, won’t be much help here, seems as though they just need a shitload of volume, and full range. Factor in decent recovery, of course.
Forearms. I started rock climbing at a gym, every other day. After about three months, my grip didnt’ even seem real, and my forearms were nearly the width of my face when flexed. I looked pretty silly, though, cause i’m 5’10", and i weighted about 155. could do some pretty silly things while crawling around on the ceiling, though.
get a wrist roller. good for your hypertrophy work. do wrist curls(in both directions!) while sitting on a bench facing down the bench with your forearms resting on it, with your hands hanging off. use a barbell, and let it rolland extend your fingers, then roll it back up and flex your wrists.
try to include some pinching work for balance.
check out Ironmind for lots of toys and resources.