Is taking a long time (than normal) to respond to someone else a symptom of hallucinations? I.E. Taking a long time to answer questions, or respond.

No. Taking a long time to respond is not a hallucination. Hallucinations are sensing things while awake that appear to be real, but instead have been created by the mind, as in hearing things or seeing things that are not real.
Yes, sometimes. While there are many reasons a person may take longer than usual to respond to someone else, one possible reason is that the person is distracted by hallucinations that are occurring at the same time. In psychiatry this is called "internal preoccupation". It can result from a primary psychiatric disorder such as schizophrenia, or as a drug effect (e.g., lsd).