I am not going to argue the last part of your post because honestly, and this is probably just because I don't understand the text well, I don't know what point you are trying to make.
For the first part, again no sources. Pointing vaguely to Wikipedia articles doesn't count, and I did try to follow up on that. There is no Wikipedia page for Russian genetics specifically (though it might be a different language) although I did some side research and genetically, there seems to be a small amount of Mongolian genetics (0.7%) in the Russian population. I also found sources that said Genghis Khans specific genetic marker was not in actual 'Russian' Russians, just Kazakhs, Buryats and so forth. You really shouldn't compare the racial mixing of the Americas to the Golden Horde in Russia because in the Americas there was large scale, intensive colonization and subsequent migration to a territory as well as a serious shrinking of native, pure bloodlines through disease and warfare which led to a large percentage of mixed race peoples leftover. Even then, different areas behaved differently. When the Spanish had large migration to Latin America you have large mestizo populations while in a lot of British North America there isn't much. Or, the French fur traders intermarried with natives to form the Metis while later colonists didn't, and remained more solidly European.
With the Golden Horde, the Mongols did what they did in China-take over the upper layers of government and extract tribute. There was no attempt to my knowledge, to thoroughly colonize Russia which would have led to a large percentage of mixed race Russians. That .7 percent of Mongolic genes then, seems to make sense for just isolated incidents of wartime rape lingering to the modern era(there are about 6-7 centuries of gene drift and flow between then and now anyways). It wasn't racial subjugation whatever that means, but a cultural and political one.
Remember as well, many historic buildings are restored multiple times. Very rarely actually, is a building unchanged from when it was originally constructed say in the 1300's to now. You make the assumption no state could have constructed those monasteries in that period without any actual evidence. I actually looked up some specific monasteries, like the Danilov monastery and a glance at information from its official website says it was restored and destroyed multiple times since its founding by Alexander Nevskys son in 1282.
Saying the biggest empire in history left no evidence is just....you have to prove that every single artifact, text, building, site from every single Mongol Successor Kingdom is fake, and that for starters, the entire city of Karakorum at Erdene Zuu Monastery in Mongolia isn't well, real. Don't forget to dispute the entirety, every word, of the Secret History of the Mongols and Rashid al-Dins whole corpus of work, who ironically is mentioned later in the article. Also, every artifact anywere in Eurasia conventionally linked to the 'Mongol Empire'. Its like trying to prove Charlemagne didn't exist, or the Abbasids were really a entirely politically different state and all their evidence is misread. Its gargantuan. The conventional narrative of history exists because it is the most widely agreed upon view of history in that time. Now, that narrative is very often incorrect-but there are scales of error and it is one thing to argue for say, a misunderstanding of Mongol trade relationships with the Mamluk Sultanate, and another to say just the entire Mongol Empire either didn't exist, or is something totally different. That margin for error also, gets smaller the closer you get to the present era. Its a lot harder to make big narrative-shifting statements about events in the 1300s AD than 1300s BC as a general rule(and I should know, my other mod was Age of Bronze

)
The last point has no evidence backing it whatsoever. I did do some reading from Rashid al-Din in the Taʾrīkh-ī Ghazānī, the part that mentions Genghis Khans life and I found no reference to the appearance of his sons that corroborates what you are saying.
I have considered this info but its just, I can't use info that isn't properly sourced. The article you linked was built on misconceptions and loaded with statements that weren't backed up by accurate period data, and I can't use articles like that. Its just the way I have chosen to work on the Mongols.
Sources:
https://www.sciencedaily.com/release...0519131507.htm
http://msdm.ru/eng/index.htm
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2253976/
http://unesdoc.unesco.org/images/001...6/108630Eb.pdf