Joseph, Rabbenu Tam (Bechorot 2b d”h shema itchayev) and the Meiri (Avodah Zarah 2b and 6b), say that gentiles are not prohibited in avoda zara b’shituf as does the Rema (Orach Chayim 156:1).
Nishtdayngesheft,
1. Please cite the source that says that two gentile women are over. Rambam (hilchot Melachim 9:5) only says mishkav zachor.
2-4. I agree 100%.