theres a similar ritual monster called:
As you can see her effect is similar to the one of the Phantom beastcraft, she targets 2 cards on the field aslong those cards are face up She can't be destroyed by cards effect. And according to the ruling that northwemko gives says:
- If "Divine Grace - Northwemko" and one of the cards targeted by its effect are destroyed at the same time, "Divine Grace - Northwemko" will not be destroyed.
So even if the targets are dead northwemko completely survives. Meaning even if the tokens are destroyed the Phantom Beastcraft also stays alive.
But this is how I will play them until the official ruling for these monters comes on the next expansion.