Mmm, see where you see problems, I see interesting plot twists. I'm not sure if the Master could project a false aura-- although I'm sure he could work on perception filters that would likely make Lorne more readily ignore any aura he sensed... of course, he'd have to know to do this beforehand.

But I also do like the idea of the Master getting up to sing and Lorne just being horrified.

What would Lorne do, exactly, if the Master struck him as suspicious?