she is at seeker camp

in case if she isn`t at the seeker camp she is at a caravan near the door where magister borris is

Yes. You can have up to four. There is a mod that makes you able to have unlimited companions.

Because he's not an origin character. Dude's a generic.

É um recurso mágico incrementado nesse jogo, você vai ganhando mais conforme avança

Fane is good at anything, Ifan wants to deal physical damage to synergise with his wolf, Beast wants aerotheurge (probably melee staff man), Lohse wants to deal magic damage cuz her source skill is resisted with magic armor, Red Prince's innate abilities deal magic so would be wise to capitalise on that

I use Lohse as polymorph/heavy cause you get OP tentacle lash which is OP with physical armor (and scales with strenght), then just invest points in warfare till you get onslaught and she becomes a tank, and adding eg. wings/phoenix dive makes her able to land first hits.
Fane as usual- necromancer/aero mage, mostly focusing on aero, then after unlocking grasp of the starved deals huge AoE damage.
Red Prince as summoner- remember that from 10 summon lvl you get a huge incarnate champion which basically is a second tank.
Sebille as ranger with lvl1 scoundrel - adrenaline (+2AP) + flesh sacrifice (+1AP) stack nicely with ranger abilities like ballistic shot, tac retreat, barrage etc

Ifan: Summoner with the “Pet Power” gift bag.
Sebille: Equally good as Ranger or Necro
Red Prince: Pyro Mage or Sparking Swings battlemage
Beast: Usually a Mage dual-wielding wands (dodge stack).
Fane: Excellent at everything. Poison absorption gives him a small advantage as a 2H frontline warrior. Heal him with your Geomancer.
Lohse: Generally a Pyro/Geo mage, as her ability can fill a CC gap or two.