Toyguru just answered my question about what PoP will look like in MOTUC. There was confusion because in the past we were told it would solely be based on the vintage toys and NOT the Styleguide...then we got Adora and She-Ra that are straight FROM the Styleguide.

Anyhow, here's the new official answer:

If a toy had a vintage version, the colors will be based on the toy's colors. As for the exact sculpt, that will likely be a blend of the style guide and the vintage toy based on the preference of the Horsemen.
So...yay for Styleguide Catra (probably). Now I have to beg the Horsemen for toy versions of everyone else!