Is this referring to the OEM colors or the harness of this product?If youre using a harnass like Axxess 1731 it should be the green/purple wire. https://metra-static.s3.amazonaws.com/documents/INSTXSVI-1731-NAV_web.pdf
Are those going to be under the armrest or somewhere in driver's side footwell?Yes, see my previous response (before yours) and check the link.
The Red accessory or you can use the green/purple