Must one make up for missed Ramadan fasts from many years ago, or is the obligation to make them up waived due to the passage of their specified time, especially given the difficulty this entails for some penitent women?

The majority of scholars view the fatwas you have come across as closer to caution and piety, citing the hadith: "Leave that which makes you doubt for that which does not make you doubt." The hardship of making up many missed fasts is not an excuse, for a person must make them up to the best of their ability, "And Allah does not burden a soul beyond its capacity."