According to the FAQ, there is an Action slot between assigning damage and dealing damage.

My question is if an action removes one of the units (defender or attacker) from play in that action slot, does the damage already assigned and coming from the removed unit still counts in the dealing damage phase?

Example:

Crooked Teef Goblins 1/1 (orc, attacker) vs Talabheim Detachment 1/2 (empire, defender)

Tababheim Detachment has "Action:Spend 1 resources to return this unit to its owners hand".

If that action is activated in the slot between assigning phase and dealing phase, thus returning the defender to the owners hand, does the orc (attacker) still receives the 1 damage?

The damage for Followers was already assigned to them; they'll get it as long as they're there or damage gets cancelled/redirected.

Crooked Teef Goblins will get damage i mean, not 'Followers [of Mork]'