There’s no clean good pictures of a 31BM with countermeasures, but there is one blurry photo out there, other than that no other MiG-31s have countermeasures besides 31M.
However none of the 31BMs you sent pics off have CMs.
Early MiG-31 as mentioned below doesn’t have countermeasures, but also it’s cockpit wouldn’t work that great for sim and the sort, most of the important stuff is in the WSO suite.
We have F-14A at 12.7 with similarly performing missiles, so MiG-31B will probably be around the same. Matter of countermeasures is gonna be difficult to solve, outside of just giving you Flare/Chaff rounds for GSh-6-23.
MiG-31BM ain’t going any lower than 13.7 with R-37Ms and at this point countermeasures are pretty much needed. Imo, the best MiG-31 to add is unironically MiG-31M but there is little to no information about its flight performance, and it should be a good chunk better than MiG-31B
BaZ tactic on medium/short distance still require flares what will be pretty common as majority of players most of time multipath (at least this is how it was in late days of nuclear event and in sim from my experience). R-33 attacks from long distances will be pretty often ineffective same as it is with other similar planes with similar missiles.