I've read & heard that very story since I was a kid being that my Maternal Grandmother is Native American, no argument in that fact, 25,000 years which can be debated give or take a few thousand adverse to 500 years which is well documented throughout history. The premise here, the native American has more of a justified claim of squatter's rights if that term may be used. So as you stated, no indigenous people exist technically, maybe with the exception of those created in the Garden of Eden.
So in the year 2104 what do you think we should do to be fair to everyone no matter when their ancestors came to the American continents? I see that as the key question that needs to be answered. Should you pay less taxes because you are 1/4 Native American? Should a black person pay less taxes because his great grandparents were brought to America as slaves?
Since life isn't fair (as is crystal clear by the horrific treatment of Native Americans at the hands of the white man) and the best we can hope for is a compromise, and since the American Indian has done nothing BUT compromise over the past 500+ years. I submit that it's time for the white man to to suck it up for a change.
Valid questions, I'll tell of the inequities committed toward the Native Americans and Blacks. The Natives were driven off their land and relegated to Reservations while the slaves served two purposes, laborers and secondly gave to the slave master voting clout since each slave was construed 3/5 person.(as if that existed in reality of an physical being) Clearly two races that had very little control over what options were offered to them. Any suggestions of retribution or any thing similar is not my position but acknowledgement that the European White man often took without the benefit of equity or fair play and consideration but rather snatched what he needed to advance his selfish agenda. From your standpoint, a "If we made a mistake, lets move on" should suffice and you're now expected to follow the very rules that put you at an disadvantage in the first place.