I have MVC2, and I have some arcade knowledge so I will try to answer your questions.
1) I don't think your MACE cab would work because you only have 5 buttons while MVC2 needs 6. Now before anyone jumps on my case, I'm assuming that you have not made any modifications to your cab.
2) If you have the layout as the typical SF layout, it still won't work because you need a kick harness to handle the kick buttons on a typical SF layout. You'll need a Capcom harness to plug into the silver box.
3) If you have the layout, and the kick harness, you can unplug your Jamma harness off the MACE board and connect it (as well as your kick harness) to the silver box shown in the auction.
My $.02