My sense is they are real people, but Peter Strzok is likely a pseudonym. I believe he is really CIA, assigned by Brennan as a fixer.
There is at least one picture of Lisa Page in a suit escorting McCabe into a Senate meeting. I think Lisa was one of the first to flip, and that is how they got all the original text messages. She was trying to cover her ass for leaking, and fingered McCabe as instructing her to…