>>2168613>>2168615>>2168616>>2168617Rei Q is only a separate character to the extent Rei I and Rei II and Rei III and Rebuild Rei and Late-for-school Rei are separate characters. The fact that the best explanation you've come up with for Rei Q and Shinji's psychic connection is a "magic loudspeaker" says all there needs to be said.
Yui and Unit 01 and such are unique and distinct entities.
It's a shame people can't simply hide and ignore things they don't like instead of demanding things be done according to their personal rules and taste.