"Can Catholic theologians, bishops, the CDF, and popes change their minds?"

There is a reason why a mind-set is called a mind-set.  And an institutional mind-set tends to be self-perpetuating.  The resignation of Marie Collins (and the hierarchy's pathetic response) demonstrates how powerful the institutional Church's self-perpetuating mind-set is.

It may be that the Spirit works more through individuals then through institutions.  Perhaps a Sister inoculating a child in Africa accomplishes more for the Spirit in a few minutes than the Curia accomplishes in a few days, or a few decades, or a few centuries.