there is no PvP (technically. unless you count festival battle boards but that's a 'get the most points beating regular enemies' thing not a 'my pets vs your pets directly' thing)
Typical party setup is Tank+Healer+Attacker,
Tank elements (abilities focus on defences and/or self-healing): Earth, Water, Shadow, Light
Healer/ Buffer (abilities can heal and/or defend other members of the party): Light, Water (water cannot be buffer under lv30, when it gets its second elemental ability. It doesn't really grow into it fully until later levels)
Attackers (full devotion to damage): Fire, Air
There's also Tank+2Attacker and 3 Attacker, with T+2A generally either being Light+2fire with seasonal festival battle board teams, or Water+2 Attackers with very late-game teams.
3 attackers is uauslly 3fire used for seasonal fest battle boards, generally only done with max, superstat, or supermax pets since they have very high hp and damage output, so they can last a long time before the player needs to heal them.
Proficiencies do matter, yes, as does equipment type
Tank pets usually get some combo of HP, offence, and Agility, exact combo varies by player and element
Healer/Buffer go offence, and then either dex or agi by player preference and needs
attackers go offence and dex
some people also just like a little extra HP on all their pets
HP is obviously, well, HP. It gives the pet more buffer
Offence is whichever stat the pet's element is aligned with (Magic/Int = Shadow, Light, Fire. Physical/Str = Earth, Water, Air) and is involved in calculating the move output of most pet abilities
Dexterity is for a pet's critical hit rate and accuracy. It shares control of speed equally with Agility.
Agility is for defences and evasion, and shares speed equally with Dex*
(* so a pet with 300dex+100agi has the same speed as one that's split 200d/200a or 100d/300a or whatever other combo)
Looking at your party pets, I see that you do not have optimal equipment on them
Shadow and Light, being Magic/Int elements, want int-based equips
Shadow should have Illusionist gear, to boost Intelligence and Agility as a Tank/slot1 element
Light, either Illusionist or Evoker (for Intelligence and dexterity)
Relics being the wrong sort is especially impactful, as relics give a direct Damage Stat boost- your shadow currently has a Myrmidon (Str/dex) which is giving a boost to her Physical Damage Stat, which she, as a Magical element, is not benefiting from at all |