The 2 step process (thrust levers to idle, apply reverse thrust and check SB up) seems logical to me (but obviously not to Boeing).
Reversers unlocked, automatically mean thrust levers are in idle position and unable to move forward at least on the 737.
As for the autobrake, a 90kts instead of an 80kts call during the T/O roll would apparently be more useful on the 737 as the A/B system won't kick in below that speed.