re: MCP
You have a point a Mechanical Counter Pressure suit is still a proto-type they haven't made a full up suit since the early 1970s.
But it would seem with the dust problem a Mark III or I-Suit would be just as much a "proto-type" as any MCP would be on the Moon. Also we have 10 or 15 years till they plan to return manned missions to the Moon.
I find Young's suggestion a waist entry would be better than a rear entry because the rear entry would have a large gasket silly. They both would have large gaskets.