I don’t see how there would be a problem with a woman trained in these halachos answering shailos for other women, and such a system may have a lot of benefit for the mitzvah of taharas hamishpacha.
Especially inasmuch as women today *are* making halachic decisions for other women in certain aspects. The main one I can think of is when a woman immerses in the mikvah, another woman makes the halachic determination whether or not the immersion was halachically valid. They also make halachic determinations regarding chatzitos before immersion as well.
The Wolf