last year doesn't really warrant a return. People who don't perform on the floor are routinely not invited back. Rose did this all the time. A new coach would be particularly likely to do this. Pope has no responsibility to bring Emery back.
Nick through his own actions brought sanctions and negativity to BYU. While Rose may have felt a need to "help" Nick, Pope won't feel the same way.
Some players may have left because they didn't want to lose playing time to Emery. Now, at least one of those possible players is coming back. I'm not so sure that Toolson would return if Emery was returning too.