Those names (Ambrose, Banks, Ryder, etc...) yes. But if a wrestler made a name for themselves outside of WWE and get signed, they will allow them to use their Indy names in WWE and allow them to use it if/when they leave.
Any name made in WWE will continue to be owned by WWE so Mercedes and Moxley will be known as Banks and Ambrose again, since those names originated in WWE.
My question is if Moxley went back to WWE and didn't want to use the Ambrose name/character anymore would he be forced to use it again?