Indeed there's no clarification on the number of votes we get. Although I don't read translations. I read the original. And it was worded like this:

"This person is the MVP." (Emphasis mine.)

It wasn't that "this person is a MVP", so I read it as that you only get to choose one from the whole party.

But of course that may be reading too far, or it may just be a mis-representation, or even it may change in the end.