Why can I only view content published to current domain?
After researching the api and reading up on how the permissions work (here) it looks as if the Node Access module limits a user (who is not user 1) to only be able to see content of the domain of which they belong, regardless of their editing permissions. You could, however, play around with grants (specifically grant_edit) to try and override the active domain. I would suggest some custom script to allow Role X grant_edit, or bite the bullet and use the "Bypass content access control" permission.

I understand this probably isn't the answer you wanted, however hopefully it helps in some way!