Multipath was introduced long before R-27s.
R-27R is closest to Skyflash, SuperTEMP, and Matra 530D, not AIM-7F/M. AIM-7F/M was such a power creep that only NATO countries that weren’t Germany controlled BVR.
R-27ER made Germany and Soviets playable in BVR, much to the issues that caused for Mig-29 future balance; Mig-29 9.12/9.13 could be 12.3 now with only R-27Rs and R-60Ms, but hindsight is 20:20.
Again, I am unsure. Couldn’t find anything about GEN-X specifically, but Britecloud (which is very similar in function) lasts for 10 seconds so I would estimate GEN-X to be more than 5 but less than 10 seconds since it is older
Well it is more of an issue as we dont have any kind of ECM to begin with, the kh38 was coded with nearly the same seekers as the agm 65D, just with a longer launch range, the towed decoys would need a completely new mechanic.
Helicopters had for a long while ircm, so it wasnt anything new, and chaff is not close to the “type” of ECM we are talking about, by that logic the US where the first to get IRCM in game…
They still need the same mecanics as the more widely aviable jammers does