You could record the piano first using all three mikes in different configurations and combine that with left & right panning in the MD8. One channel could be the "center"(probably the Sony) and the other two panned left and right at opposite sides of the piano about 4 feet away. The Sony could hang above to capture what the other two missed. Through EQ and panning you should be able to come up with something passable.
I would recommend the SM57 for vocals on the second take at about 18 inches. Tell vocalist to minimize Ps and Bs to avoid plosives. And to SING OUT so you dont need to crank up pre-amps.

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Smitty