My opinion is that Mini-Busy from Parallel Waves is 'illegal'. However, if I was dancing and a caller called it, I probably wouldn't complain too much. I'd probably have the leaders do a Turn & Deal movement (passing R-shoulders of course) to end in Tandem, offset from the center line.

Mini-Busy is often thought of as a 3-part call (From 2FL, 2/3 Mini-Busy ends in an Hourglass). The Trailers' part is well-defined: 1/2 Circulate, Very Centers Hinge, Flip The Diamond. The Leaders' part, however, isn't as well-defined. I believe the the Leaders' part is basically one motion, and that when done from Parallel Waves, the Leaders should end on the same spot, not in tandem.

I believe there is no problem on a 2/3 Mini-Busy from Parallel Waves, since although the Leaders end on the same spot, they are facing opposite directions, and hence step to a R-H Mini-Wave.

Ceder Chest Definition of Mini-Busy