I put my thrust in real FA-18 pilots, and they say the fingerlifts are only to prevent the pilot from inadvertently shut down the engines. Meaning, you have to use the fingerlifts to move the throttles from idle to stop to shut down the engines. And that is allegedly their only function. There's no mechanical stop between MIL and AB, only a detent where you move the throttle out just a little bit. It's allegedly not a hard stop, more of a bump that you can feel to remind you that you're moving from MIL to AB.
Allegedly.