Do clear, whitish discharges—which are released without arousal—count as madhiy, given that they are frequent, and are they considered madhiy incontinence?

So long as these secretions are discharged without desire, they are not madhy (prostatic/vaginal fluid discharged due to arousal), but rather they are among the normal secretions known as vaginal moisture (rutubat al-farj). One should not give in to obsessive doubts. If you are unsure about the discharge, you have a choice. If you suffer from incontinence of vaginal moisture, you should perform ablution after the time for each prayer begins.