Kokachin's fate in the final episode
My extensive research (read: Wikipedia) says the historical Kokachin's sole role in Polo's story was basically that Kublai asked the Polos to drop her off at her arranged marriage on their way home. Thus, this trip was likely why Kokachin was chosen as Marco's love interest, which means her fate is likely going to be one of two things. (1) If they're going for a more tragic Star-Crossed Lovers ending, that voyage will be the dramatic last time they see each other sort of thing. (2) Alternatively (and less likely) if they go for a happy, more Hollywood action movie kind of ending, there will be another Dead Person Impersonation with someone else trading places with Nergüi (Mei Lin, perhaps?) who goes on to Europe with Marco.- Jossed. Kokachin's arranged marriage in the show is with Jingim, which leaves her right in Cambulac. And she dies without ever going anywhere west.
The series is a Westworld theme park.
The titular Westworld is but one of many parks run by the Delos corporation. In the novel and original film, one of the other parks was Medievalworld, and in the show, one of the alternative parks is Samuraiworld. A Mongolianworld would be a nice bridge between the two parks, and being a theme park covers up the various historical inaccuracies in the show.