Difficult to say … None of your list had a significant market volume here (to say the least).
Rotring Tikky, Staedtler Mars Micrograph, Faber Castell TK9x00 holder are typical at Germany. I leave out RR600 because of the KIN at your list, but KIN Rapidomatics were not sold here (and I still miss any of them in my collection due to zero availability here).
Parker Duofold - confirmed the fact that “ordinary” people would pay serious money for an MP.
The original Sharp and Eversharp pencils - the first MP for the masses.
I’d only argue that for the KIN Rapidomatic, the original plastic bodied 563x series were more influential than the metal bodied 5640 that came after.
I’d nominate the Faber-Castell TK-matic L for being, arguably, the first automatic-feed MP, an innovative design that showed the way for the Technomatic, Micromatic, Orenznero etc.
Also the humble Uni Kurutoga for setting off the modern era of innovation in lead protection systems. No KT probably would have meant no DelGuard, Mogulair, etc.
Alternatively, we can consider the SAKURA and TOMBOW CREATE… the first sliding pipe designs, whose concept lives on today in the standard Orenz.