Companions

A man drifting on a piece of Flotsam.

Fighter or Brawler (Fighter + Monk) or Brute (Fighter + Barbarian).

Cipher or Barbarian or Witch (Barbarian + Cipher).

You can recruit him soon after you repaired your ship on Port Maje Island and set sail for the first time. While sailing the waters, you will be approached by another ship. Serafen will be on board this ship.

He can join your team.

Fighter, Rogue or Swashbuckler (Fighter + Rogue).

She can join your team.

Priest, Monk or Contemplative (Priest + Monk).

He's hiding in a cage. He can join your team.

Wizard or Battlemage (Wizard + Warrior) or Spellblade (Wizard + Rogue).

Chanter or Barbarian or Howler (Chanter + Barbarian).

Paladin or Crusader (Paladin + Fighter) or Herald (Paladin + Chanter).

Her location would depend on the result of her mission in POE1. She could be here (after you speak with the queen at the Kahanga Palace) or directly in the palace after the first conversation with the queen and the diplomats.

Druid or Chanter or Theurge (Druid + Chanter).

You can invite her during your first visit to the palace.

Ranger or Scout (Ranger + Rogue) or Geomancer (Ranger + Wizard).

Cipher or Rogue or Mindstalker (Ciphr + Rogue).

He will be here after you defeat The Messenger.

He will give you Vatnir's Icepick required to climb ....

You can convince him to join your team: Priest or Celebrant (Priest + Chanter) or Zealot (Priest + Rogue).