MGRS is what JTAC uses and the benefit is its easier to remember and enter into CDU being only 2 letters and 6 numbers.
Thought there was a "padlock target" view but didn't find one in control list. As you approach targets make mental notes of anything around you can use for reference in spotting targets or finding them again if you lose sight. After making a pass I like to look back at target to get a visual from the direction I'll be coming back from. Not the same as padlock but a couple views I like to use are "Arcade" and "Ground Hostile" view.
There are a few different Gun Reticules you can use. One is a small crosshair that doesn't block out target indicator until you're right on top of it. I do think it disappearing is a good thing though, so you can more accurately aim at target not a symbol that's much larger.