What is the ruling on not advising my female colleagues who wear revealing clothing at university, and what is the appropriate Islamic wording for advising them? Is it permissible to remind them that their lack of commitment deprives their deceased parents of reward and burdens them with sins?

Plucking eyebrows (namṣ) is a major sin.

Wearing shoes that make a sound when walking is not permissible for men or women; for women, it arouses men's desires, and for men, it opens doors to pride and arrogance.

It is not permissible to advise these women directly due to the potential for fitnah (temptation/discord). Instead, a female mahram (unmarriageable kin) or the wife can be assigned to do so.

Fathers who neglect their children's upbringing bear a share of their children's burdens.

The two girls can be reminded that their sins harm their fathers, provided that the reminder is conveyed by a woman or one of their mahrams.