I think lots of people could use the same arranger and won't sound alike unless they all play the same song with the same style with the same tempo and the same three chords in the same key and sing alike!

I don't think even two people will sound a like because there are too many style of music so on and so forth. How can two sound alike if one does Johnny Cash all night and another does Bee Gees all night.

Too much variation in music to sound alike. Seems impossible to me. You play Sinatra, Ray, Tony etc I play Elvis , how are we going to sound alike.