Is Illaoi E counted as spell damage when hitting the spirit or just the damage dealt to the spirit?

So if I illaoi E and auto the spirit it counts as dealing auto damage to the enemy or spell? If a person has dft does the dft apply on the champ and the spirit? So say Illaoi has dft and tentacle slams the spirit does that apply dft on the spirit and the enemy?

If it is counted as spell damage does that mean illaoi autoing the spirit apply dft to the enemy or no?