DSHOT MC Motors on VTOL

I’m setting up an AAEET VTOL with Quad X lifter motors running off DSHOT ESCs using the new Holybro Durandal on 1.11.3. As DSHOT is only available on FMU (aux) ports, I have it wired in the following configuration:

M1 - right ailevon
M2 - left ailevon
M3 - right elevator
M4 - left elevator
M5 - pusher motor
A1 - lifter motor 1
A2 - lifter motor 2
A3 - lifter motor 3
A4 - lifter motor 4

I have DSHOT 1200 enabled, and have been able to get beep tones out of all multicopter motors from the mavlink console. I’ve set up the following mixer files to override the quad_x and vtol_AAERT mixers:

Main:
M: 2
S: 1 0 4000 4000 0 -4000 4000
S: 1 1 4000 4000 0 -4000 4000

M: 2
S: 1 0 4000 4000 0 -4000 4000
S: 1 1 -4000 -4000 0 -4000 4000

M: 1
S: 1 1 6000 6000 0 -6000 6000

M: 1
S: 1 1 6000 6000 0 -6000 6000

M: 1
S: 1 3 0 20000 -10000 -10000 10000

Aux:
R: 4x 10000 10000 10000 0

I have VT_MC_ON_FMU disabled, and VT_MOT_ID and VT_MOT_OFFID not set, as these seemed to soft-lock the autopilot for some reason? When I arm in multicopter mode, motors 1, 3, and 4 spin up, however motor 2 does nothing. When I switch to fixed wing mode, my servos work correctly, however upon arming, the multicopter motors come on as well as the pusher, although motor 2 still does nothing. As stated before, I was able to get a beep tone out of motor 2 through the mavlink console, so there’s no communication or configuration issue there. Any help or advice would be much appreciated!