When and how will I be able to run elementary on Mir/Wayland display server? Is it going to be possible on the first release of Unity 8?
ElementaryOS is in migration (or anything like this) to Wayland and is a long process to begin the default session but you can test it with
gala --wayland in terminal, about Mir and the unity 8 release this don't support another Sessions for now only the Unity and the ubuntu touch
I hope this answer your question;
Sorry my Bad English XD