Since I cannot translate properly these answers from Yuri Pasholok, I will summarize them:
-Matilda I will not come since it is armed with weak MGs.
-Christie tanks are very weak, like tier 2. Hard to implement since they are poorly armed too.
-E-50 is not completely fake, the rear transmission was planned, this is unique to the E-50 and E-75:
-Swedish tanks confirmed (EMIL 1951, AKV 151, Kranvagn) – but they will not be implemented all at once;
-Japanese HTs are up to 150 tons heavy;
-there is another heavy Italian project, called the T-39, it is unlikely to be implemented.
-Some Japanese tanks are riveted (early ones), some are welded;
-Chinese SPGs are similar to the Soviet ones too;
Q:Developers once said that there is a project of a French post-war tank with a 400 mm armor. Say what?
-Well, not 400, but like this: