Yes, a rising star so valuable to the record company that your name is put on a screen to be swapped out for the next guest who walks in after you leave. Nobody is playing along and buying into the illusion that these are posters, not screens. The interactivity is so impersonal that it's just asking too much to suspend disbelief in order to make the effect work. Furthermore, neither you nor anyone walking through those queue doors is a Prince or an Adele, so the choice of "Stephen" or some such as a stage name for a relative nobody strains credulity, to put it mildly.
In the pre-show, the band members' dialogue includes such lines as "We can't leave these people behind" and "You know how we feel about our fans". The guests are just that - music fans. Your theory relies too much on ambiguities in the pre-show dialogue and assumptions when a simpler explanation can and has sufficed for years, and no one is buying into it. Part of the magic, if you will, behind the attraction's premise is that the guests are just ordinary fans who are lucky enough to get a limo ride to the Aerosmith concert. Ask guests to believe that they, too, are professional musicians, and the magic diminishes a bit. One of the gags is that the band has to order a super-stretch limo to fit everyone. Again, it's asking too much to believe that you're in a room filled with rising stars in the music world. In contrast, you don't have to suspend disbelief all that much to buy into the illusion that you're being ushered to the concert in a huge limo with fellow music fans.
I also disagree with your characterization of the Storymaker posters as a "small detail not everyone will see". These interactive screens are staged so that guests will notice their names. But suppose we accept your premise that it's a small detail that only the fans will notice. Does it justify the money spent on the effect if few people are supposed to notice? I don't think so. Why not just leave the real posters then? They've done a better job at filling the role of staging detail for years.
These new posters for RNRC are a storytelling mistake and an example of technology being applied where it is not needed.