Andean Coot variation at Pantanos de Villa

On November 26, 2007, I took a series of photos of the coots at Pantanos de Villa. The variation is extreme and I suspect there may be genes in the population from other species. The question is which species.
The background is the strange coot I found at Pantanos de Villa on OCt 15, 2005 which has many traits of Red-gartered Coot Fulica armillata.

NORMAL ANDEAN COOT VARIATIONS

Normal Andean Coots should look more like the ones below

White or Yellow forehead with white

With yellow forehead and white bill

With Chestnut forehead and yellow and white bill

Or Chestnut forehead with almost completely yellow bill

STRANGE COOTS IN VILLA

But these ones are far from normal. Foreheads are less bulbous and orange or red in color.

Red forehead - yellow bill

Orange forehead and Yellow bill

Red forehead with orange margins and completely yellow bill

Orange forhead and yellow and white bill.