Interaction of Intellect Devourer’s actions with the Protection from Evil and Good

How do Intellect Devourer’s actions interact with the “Protection from Evil and Good”? Am I right that:

  1. if “Body Thief” was not successfully used and the target creature is already under spell, than:
    1. “Claws” attack has disadvantage on attack rolls,
    2. if ID uses “Devour Intellect” does the target have an advantage on Intelligence saving throw (looks like it’s not stated directly in the spell’s description, there is just said about this only if the target is already “charmed, frightened, or possessed”) when ID uses this attack for the first time? For the next time, if previous failed?
    3. ID cannot use “Body Thief” at all.
  2. if “Body Thief” has already been used successfully and the target creature was not under the spell (which is a consequence of the previous statement, otherwise it cannot be), than:
    1. ID’s attacks (on the first target) have no meaning because the target’s brain is magically consumed and ID is in the target’s skull,
    2. casting “Protection from Evil and Good” on the target with ID inside with 100% chance drives the ID out.

Am I right? Please, pay attention to the 1.2 statement.

Actually, this question is not a duplicate of this: Protection from Evil and Good and Intellect Devourer because there was asked only if the Protection from Evil and Good can drive the intellect devourer out of the body as is stated in the monster description while in the spell description it is stated that it can affect only the creature (not body).