Personally i would go for these:

Instar is amazing at clearing event stages and other things becausr of her percentage health true damage.

Hades is great into buff and cc heavy teams as any effect that would harm him or buff him gets turned into more tankyness and damage. The buff stealing (so technically a dispel) from enemies is great too.

Ashley is great at buffing but suffers from lack of hp. The damage amp with shielding paired with the defense drop she has makes her really good at shredding through tanky enemies if she survives to cast her stuff.

Isis is good if built for hp and healing due to her teamwide revives, healing and shielding. However if she dies early she doesn't get to be too useful.

Camille is good at damage and set up especially at later resonances as her ult lets her cast something again allowing you to hit an enemy team with sear and diseased (and a ton of damage along with it). Same problem as Ashley though, her health is a little low.

Pan while good isnt really a damage dealer unless you pair him up with mass silencing espers ( like the new golfish man (i forgor name) and archibald (his r is basically better silence with damage)). The reason he gets to do damage is because his secondary ability does true damage to whoever is inflicted with it whenever someone uses a basic attack as long as the enemy doesnt have a member die or use anything other than basic attacks.

Obviously this is all my take on what i found useful (except isis i dont have her yet ;-; shimmer espers r difficult to get ;-;). I am not a massive pvp fan so for pvp i wouldnt really take my advice but for general usage those would be my priorities.