My question about the coins was not answered last time, but I've determined that simply playing through Classic and All-Star accumulates the most coins... I think.

Now, a new question: In the Subspace Emissary, how the hell do you turn bosses into trophies? I read that this was somehow possible, but I'm not sure how... are you just supposed to wait for a trophy stand to appear on the field and toss it at the boss when he has nigh health left? That... would be very taxing, to be sure.