yeah those portraits have something large format-esque going for them. I like them, except mabe the diver/squid one - that almost looks like he is a cutout.
while the leave shutter makes this easier, what speaks against shooting at 1/250th (some focal plane shutters pull that off) and a strong ND? (You'd have full frame with shallower DOF at same aperture etc.)
anyway - good portraits!