"Gripping Beast Medieval Russians - time period?" Topic

I recently received some Gripping Beast Russians from this range (got them from the U.S. distributor Architects of War, who were great to deal with!):
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Since they feature Alexander Nevsky, I am assuming they can be used from the time of the Mongol Invasion (1200s) but not sure how long after that. I have always read that Russian equipment was more conservative than Western European styles, but could these figures be used up to the time of Ivan the Terrible or is that too late? I am guessing by that time (mid-1500s)there would be more emphasis on gunpowder weapons so the infantry crossbows probably won't work, but would the Gripping Beast cavalry still be acceptable for that time?
And would these figures be acceptable for other Eastern European armies of that same time period – I am guessing they would be fine for Lithuanians and probably Poles too, but how about Serbs, Hungarians, Bulgarians, etc.? I was thinking of making a medieval Serbian army using a mix of Gripping Beast Russians along with more 'western' knights. Any advice would be greatly appreciated!

Those figures are good up to introduction of firearms and beyond. Later cavalry, 16th century could have holsters on their horses for pistols, just like any Western cavalry. By the second half of 16th century this equipment will be old fashioned, but still available.

I think that GB range has too many "fancy" looking cavalry. Equipment would be simpler for most cavalry with Persian looking tall pointy helmets and simple mail. GB figures are definitely Byzantine style and Russian icon influenced.

I use the figures for later Byzantines, 12th to early 15th century. Bulgarians, Serbians, Eastern Poles, Lituanians and probably Eastern Hungarians were heavily influenced by Byzantines and would have similar armor.

BTW, i have too many armored horses for that range and if you want to swap un-armored for armored horses I am in.

And getting them to fit on the horses -good luck with that.