I ran my el Mariachi with gears and as a single speed... With the same dropouts, which is pretty rare on a bike frame. I also ran it with regular 29" tires, and 27.5+ tires. It really is a "do anything" bike.
Wish I still had the extra cash to pick it up, with home improvements and surgery, its just not in the cards right now. It would make a great Bikepacking bike.
The only snafu is the rear hub, which is singlespeed-specific (no room for a cassette). I ran the bike with a different wheelset that allowed me to switch back and forth between SS and geared. Other than that it's an easy conversion, and the bike includes the dropout for a derailleur.