"While installed in this manner, can the can the A2/Purple negative input lock trigger and A3/PurpleWhite negative input unlock trigger wires be used to send lock/unlock signals onto the CAN BUS?"
- Yes, These wires are inputs, so if they get a ground the vehicle will either lock or unlock.
"If yes are there any restrictions? If EVO-ALL alarm mode is enabled, must it be disarmed first, or will negative unlock trigger via A2/purple still operate?"
-A2 or A3 will arm/lock or disarm/unlock the evo and the vehicle when in alarm mode.
"The intent here is to create an alternate mechanism to unlock the car for when it is more convenient to leave my keys inside (with FastKey properly RF shielded of course). If the CAN BUS lock/unlock interface in the EVO-ALL is enabled in this mode, then that will make the installation trivial as it is already present. Thank you."
- Just my opinion, I would not recommend this because this would make your vehicle incredibly easy to steal.