Remember that NA was the result of a few major events. I'm not as familiar with Siberia.
With the growth of magic and the realization of many animist beliefs as being grounded in truth, the ainu have likely experienced a resurgence and gained some measure of prestige, focused around Hokkaido. There presence in Neo-Tokyo is likely minimal, though it's not impossible that they have representation in the diet, especially given the Emperor's reformative actions.
Ryukuan groups may be trying to leverage more recognition, but given the history, it's less likely that has gained much traction.
In either case, I don't think an Ainu or Ryukuan heritage is given much thought to folks living in Neo-Tokyo unless that individual is an agitator.
This is mostly my observation, not hard canon.