Is there a way to edit multiple user roles at once? Could be built-in functionality or a module. The site's users will have several roles that all expire on the same day. If those roles have to be updated manually, is there a way to update the expiration dates all at once instead of doing them one at a time?

Seems that I'm carrying only bad news today - no way, sorry

I suggest you look into 3rd party modules that allow you to export and import users, including their security role assignments. With this, you may potentially export the users with role data to Excel, do your updating in Excel, export to csv, then import back into the same module. I'm not absolutely sure this will work for you, but I recommend that you investigate. I would look into Mandeeps.com for their Live Utilities module, and the store.dnnsoftware.com for "Bulk User Manager," "Power Import & Export" and maybe more.