Adapters to install a V-brake on Magura mounts are available but you can make your own cheaply: one way to put V-Brakes on Mag mounts (photos are later in the thread)
It’s a Tektro 857AL (arms are 110mm long). On my 26" there is slightly less clearance between the crosswire and tire than there is between the frame and the tire so I’d say a 3" tire would work but there wouldn’t be much mud clearance.