If you're curious to see what kind of controller layouts are available on the current demo build of Halo 5: Guardians, I had a chance to record the full menu at Microsoft's Gamescom Showcase.
We get Default, Southpaw, Boxer, Green Thumb, Bumper Jumper, Recon, Fishstick and Halo 4 for buttons, and Default, Southpaw, Legacy and Legacy Southpaw for sticks.
You can check the video out just below: