This is a bit off the beaten path...
I have found that there are people whom, at their death bed, do not recognize their own relatives. So, I did an experiment on this. The suggestions were as follows:
"I want to introduce you to someone you have never met before." I then introduced the subject to a person he knew, but showed no sign of recognition. The subject said, "Hi. My name is..." to whence I added, "And now you recognize him."
The subject looked startled. "Oh! Hi! I'm sorry, I didn't..."
Me: "And now you don't recognize him."
Subject: "Wait a minute. Oh, I'm sorry, I though you were..."
Me: "And now you do recognize him."
Subject: "Hey, aren't you..."
Me: "And now you don't recognize him."
At this point, the subject turned to me and said, "What are you doing?" I explained that recognition is a switch that the mind toggles on or off. Unlike an emotion which can be volumed up a little or a lot, recognition either is or is not there.
My next experiments in this field will be to introduce total strangers to a person and see if there is any possibility of recognition without tangible data. I know there is something along this line, for once I asked a person to go back to the very first time she met her boyfriend, and although she clearly thought she knew, her mind came back with an event three years before, while she was on a bus. He came on the bus and said, "Hi." and sat down. That was all that happened, and still the brain remembered that he was one and the same.
People Replacement
In introducing people to other real people who are convoluted in a suggested illusion, mere recognition is not a limit. If you introduce a subject to a person that is in the room, but suggest that this person is a star which they are a great fan, the illusion is far greater for the anticipation is excessive.
However, there is a point to this type of replacement caricature. You can introduce them to a person which is an embodiment of the person that they wish they could be. It would be like looking in a proverbial mirror, but also they can tell you what this person can do that they cannot, and help you understand the subject's emotional weaknesses, so you can help them strengthen their personal beliefs and self-esteem.