Yes. Some parasomnic events may seem to be very realistic but hallucinations.
Yes. A hallucination is an experience in which a person sees (or hears, feels, or tastes) something that seems real, but is not really there. The person is awake (can be in bed) during the hallucination. Causes include sleep disorders, delirium, chemical imbalances (liver or kidney failure), drug abuse or withdrawal, medicine effects, psychiatric illnesses (schizophrenia, ptsd), brain tumors, etc.