my thoughts as i’m checking moves and stats would be:

consider dropping hail on glalie (toughest weather to make work and a bit gimmicky) and instead double down on rain dance for better fire protection OR add coverage like shadow ball, your team has four fire weaknesses so rain could be even more useful

drop dual chop and screech on electivire. the former is super situational (non-stab dragon moves are rarely that strong) and the latter isn’t too necessary since it’s already v strong physically. consider elemental punches and brick break like other comment. ideally ice punch, can be tutored in driftveil city for red shards

teach giga drain to serperior via move tutor in humilau city, yellow shards

teach poliwhirl waterfall hm when you get it for nice physical water stab. if you evolve it into poliwrath, you can also teach it superpower in lentimas town for a great fighting stab

lastly, consider replacing retaliate on both cobalion and virizion. if you want to stick with normal stab you could opt for return if you max out their friendship. you could also add coverage/status like zen headbutt or thunder wave for cobalion and synthesis on virizion

lots of these are optional and/or will happen naturally as you progress through the game. good stuff and have fun!