A token's owner is the player who created it.

Gaining control of a permanent doesn't cause you to gain control of any Auras or Equipment attached to it. They'll remain attached, but their abilities that refer to "you" still refer to its controller rather than you. The controller of such an Equipment can activate its equip ability to move it back to one of their creatures during their main phase.

The owner of a card is the player who started the game with that card in their deck. If the card didn't start the game in a deck, its owner is the player who brought the card into the game, via Living Wish or a similar effect.