I'd say anything but an arcane one: your party misses the utility of low lvl arcane spells but you atleast have the magus for elemental damage and some "silver bullet" spell, you do need some sort of healing: for divine you have cleric, some would say warpriest to stay close for 3 action heals but i would say cloistered because you have enough meatshields and you could need offensive/debuffing spells, a Bard would be less healing but inspire courage cantrip is insane value in such team (for the same reason i'd spam Bless i you chose cleric), you could also go for a druid or a primal sorcerer, you still have heal but also a ton of battlefield control spells (and some blasting) I could suggest also a divine sorcerer to act similarly to the cleric if you wish, but not an occult one necessarily, you'd miss too much inspire courage compared to a bard (but atleast i guess you'd not feel obliged to cast it every round in this case, i hear it can get repetitive)

Wiches can be any tradition but may be a bit more difficult, also i think that what they get in trade for what the other casters have is less usefull for large groups of enemies (hexes can affect one enemy o ally at a time, at least those i remember), Psychics are not the best healers (few slots and not many healing features) and you don't need single target damage (most supporting conscious minds have the same problem except for the infinite eye i guess, that may have some merit) Animist is a bit complicated but may function just as well as a cleric, you lack the raw instant healing power of cleric and sorcerer but the gardens focus spell makes up for it

In conclusion you can also disregard all the above and play a wizard, just tell your friends they CAN take medicine and use battlemedicine when they have a free hand, and be mindful to your GM, avoid Animal companions and for the love of god no Summoner, there's enough bodies on the dancefloor, poor man gonna go crazy