[should i use regigigas or garchomp?]

I have a lvl 100 garchomp and just caught a regigigas. my team consists of Charizard y, metallic venausuar mega, swampert mega, garchomp, groudon and zapdos
all level 100. should i keep my team or replace one of my pokemon with regigigas

[who should i replace with groudon?]

Hi, im new to this game and by going around in scorched sanctum i caught a groudon. now my question is who do i replace in my team with groudon?
my team: charizard y
             zapdos
            tyranitar
            garchomp
            swampert mega
           metallic venausuar mega

[What pokemon should i add to my team]

btw now i have a lvl 100 zapdos
what should i change in my team

 

oh i forgot the moves
charizard y Blast Burn, solar beam, dragon pulse, air slash
garchomp dragon claw, dig, crunch, fire fang
tyranitar  stone edge, crunch, earthquake, thrash
swampert (mega) surf, earthquake, ice beam, hammer arm
zapdos  discharge, drill peck, ancient power, pluck
metallic venusaur (mega) sludge bomb, frenzy plant, Giga impact, earthquake

[What pokemon should i add to my team]

right now i have garchomp lvl 100
                      charizard Y lvl 100
                     swampert mega lvl 100
                     zapdos lvl 80
                     tyranitar lvl 100
                   metallic venusaur mega lvl 100