If a double-faced card is exiled and returned to the battlefield with Touch the Spirit Realm or its channel ability, that card will return to the battlefield front-face up.

If Touch the Spirit Realm leaves the battlefield before its first ability resolves, the target permanent won't be exiled.

Auras attached to the exiled permanent will be put into their owners' graveyards. Any Equipment will become unattached and remain on the battlefield. Any counters on the exiled permanent will cease to exist. When the card returns to the battlefield, it will be a new object with no connection to the card that was exiled.

If a token is exiled this way, it will cease to exist and won't return to the battlefield.

Discarding the card is part of the cost to activate a channel ability.

If a channel ability requires a target, you may not activate it without a target just to discard the card.