And D ICE R, 'Mentalism' defined:
1. Parapsychological activities, such as telepathy and mind reading.
2. The belief that some mental phenomena cannot be explained by physical laws.
Obviously everything magicians do can be 'explained by physical laws,' but, not by laymen.
So, in a case where he provides objects, the spectator has a free selection, to which he provides a prediction in a fair, clean manner, is - in my book - mentalism.
Firstly where did you get that definition of mentalism from, and secondly using your definition of what mentalism is how does the effect bench mark to that.
My primary problem with the effect is you have openly stated you are going to influence the spectator to think of one of 6 celebrities. So any procedure which diverts from think of one got it ok instantly takes away from the parapsychological nature, which mentalism is based on.
The most important aspect of mentalism is the mentalist, he has this power either by something psychic or as become popular now days and amazing understanding of NLP and suggestion. But ultimately at the end of the day the mentalist as a power/skill that he is demonstrating. The effect in which he chooses to perform should demonstrate this power and should follow the most logical procedure.
In this effect by asking someone to choose a celebrity by selecting a number feels illogical especially considering the names are openly displayed. This will make the effect feel like a trick and inturn the apparent nature of the mind reading is lost and you merely become a magician again. When the audience believes something has happened it is just as bad as if they know what has happened. This contradicts the second point towards your definition of mentalism.
We can discuss this further if you would like. However if you are truly interested in mentalism I suggest you look into Fundmentals by Bob Cassidy.
Actually while you are at it I suggest you look at The Master Mind Reader himself perform after looking at either of these two presentation compared to Spidey's effect you will instantly why this is mental magic and Bob Cassidy is a mentalist.
http://www.youtube.com/watch?v=IQpVZ9xQW-8 Remote Viewing (so much out of one move)
http://www.youtube.com/watch?v=UC-rwZdqckA 4DT the best mentalism effect ever created.