Your question is right on. But I bet it is not going to be answered because it is a bunch of hogwash.
Its like the many blond San Blas Indians here in Panama. No one bothered/bothers to come here and look into their rapidly shifty quivering blue eyes aside from other physical features. They would find they are albinos. The San Blas Indians have lived on islands off the coast of Panama for a zillion years and do not like intruders.
These albinos are caused by interbreeding and nothing else no outside Euro influence.
Curious, I looked up human albinism at Wikipedia, and found that eye color does range, and...
"...Eye conditions common in albinism include: Nystagmus, irregular rapid movement of the eyes back and forth, or in circular motion..."
“They would find they are albinos. The San Blas Indians have lived on islands off the coast of Panama for a zillion years and do not like intruders.”
Their language is speculated to have split from chocoe only ~5 centuries ago (just a philologists’ estimate based on drift); the obvious answer is the island-dwellers dialect began to shift from the mainland shoko around the time they began living on islands.
some islands (not the major ones) have inhabitants that, if taken without costume, look more like choko than kuna (or guna, as they seem to have changed it to now).
The mummy thing in peru should be prety easy to resolve with dna testing, lack of anything public isn’t encouraging.