"This would be a non-issue if they were regular paintings."
This IS a non-issue. It gives people a chance to show off their sensitivities. Don't like it? Don't look. Think it's art? Die while trying to protect it.
Hire a team of lawyers at public and private expense and cost everyone a fortune, that's what should be done. That way the lawyers can get richer, the preservationists can be heard, the native people can be represented and politicians can blow hot air up everyone's asses after licking their fingers to see which way the wind is blowing. There is a much simpler solution, but it is too obvious. tim