You mentioned that 'LEAP does not support mutual auth from the perspective we're interested in, but the other methods are at least capable of it.'
Some may get confused mutual authentication with pseudo-mutual authentication.
According to the CWSP study guide (Sybex, 2010), LEAP supports a 'look-like' mutual authentication that actually is not a 'real' mutual authentication as PEAP, EAP-TLS, and EAP-TTLS support.
Can we say the following?
(1) From the perspective on discriminating the supplicant and AS, LEAP provides no mutual authentication.
(2) From other perspectives, LEAP provides a very limited mutual authentication, i.e. pseudo-mutual authentication.