MAME4droid v1.01: Undocumented features?

I'm using a standard Wiimote when playing MAME4droid on my tab, but I kept hitting the controller's back button by accident, and exiting the game.  So I went into the settings and defined the back button to "SELECT' which I thought would be next to turning it off.  (Setting 'BACK' to another button only gave me two 'BACK' buttons.)  Turns out with this version of MAME4droid, 'SELECT' is actually 'add coin'!

But it gets better.

I had also set the 'A' button to 'START' on my Wiimote, and while playing today, accidentally hit 'START' and 'SELECT' together. The in-game options menu appeared!  We may not have save states, but we can cheat.

Unfortunately, it's Monday and have to get to work.  No time to test any of it out and questions remain:

Will a normal cheat file work?
What is a watchpoint?
Will MAME4droid remember the cheats I find?