I think that for the flat pieces with holes, that I would have them punched out on a press (sub-contract). That way, the only thing left is the tapered sides and the countersink of the holes.
Countersinking could be done manually on a drill press.
I would build a custom machine which used a metal cam the same shape as the part to have the taper. I would have a motor (geared or stepper) to rotate the part slowly using the cam to hold the tolerance of the part. I would use a very fine grinding wheel to put the taper on the sides.
So far, no machining.
Setups: Vice on drillpress with countersink bit - depth preset.
Setup for edge grinding. Install metal cam with a couple bolts - grinder is spring loaded to hold a bearing (etc) against cam to hold grinding tolerance. No high dollar machining equipment required. No high dollar labor required. No knowledge required.