Deeply frustrating evening. However, I did get the solenoid valve installed on the accumulator (which has about 1.9 qts of oil in it now!):
And got the MAP sensor installed on the vacuum manifold (yes, both the hose and mounting method are temporary):
...and ordered about $150 in -10AN fittings so I can basically re-do all of the plumbing on the engine side of the oil cooler thermostat because the Universe has stuck gamely to the irritating rule about multiple things occupying the same physical space (i.e. they can't).
edit: oh, forgot. I also got the oil pressure sender installed since the M12x1.5 male to NPT 1/8" female fitting I needed to adapt the ports on the oil filter manifold to the sensors finally showed up.