Mazacoin is supposed to be a "sovereign currency" anyway, so what does it matter? If it is true that the Lakota Indians approve of and support Mazacoin, then let them secure the blockchain and trade the coin among themselves. Why would the coin need to be approved by non-Lakota Indians for the actual Lakota Indians to start using them? That thinking seems to run contrary to what the goal supposedly was. If the fear is that malicious third parties may drive the value of the coin down if they are not appeased, then that should have been considered before it was heavily promoted to people who are primarily interested in making a profit from pumping and dumping coins.
Yes, Mazacoin needs a high value against the US dollar for the citizens to adopt it as the dollar is the currency in use. They do not live in complete isolation from the rest of the world. Keep in mind that those nations do not own their land in the way most nations do. They have the use of it through treaty with the US, like Great Britain had the use of Hong Kong. This is an immoral stance for the US in my opinion. However, that's a different though not unrelated issue as it demonstrates the position they are in with regards to the power the US holds over those nations to force them to concede to US commercial or government interests that desire to exploit that land or whatever they want. Mazacoin as a currency would be a step in the direction of self determination for those nations.
Since Mazacoin isn't backed by gold and doesn't have widespread use, it has to get that value against the dollar from exchanges. As Mazacoin is gradually, over time, being accepted and used as a currency, it will function as a means of generating wealth to those nations that mine it and trade it. The promise of wealth and ease of use over fiat generates acceptance. So, yes, the exchange value is very important for the citizens of those nations to adopt and use it and improve their standard of living in the process.