I second Graham’s opinion in that I think many seemingly unfit candidates are simply lost sheep. Some women are stubborn, want what they want and don’t really care what you, the Church, or anyone else has to say about it. To single out the “tainted” women in the Novus Ordo, I’m sure some know about the errors of VII, modernism, feminism (etc.) and still persist in their ways. But there are also many spiritually dead or dying people in their places of worship that really are well-meaning people who would make excellent Traditional Catholic mothers.
I do believe if you were open to trying to convert them, God would work miracles through you. Many times has He beautifully done it before. Weeding out all the pollution in her mind might be a great task and one you doubt you’re fit to undertake: but that poor lifeless soul is one that our loving Savior shed His Precious Blood for, who might not be saved otherwise.