Borrowed a set of 27,5" wheels with 2.2 mtb tires on the local bike shop to test fit on my Checkpoint ALR 4, clearances are good even with the rear dropout all the way forward. No problems with the FD either.
The front wheel the lbs had was a 15mm thru axle so I did not fit it on the bike, rear dropout is all the way forward on thos pictures, Total wheel diameter is just a little bit smaller then the 700c wheel with the 40c Maxxis Ramblers.