Is it obligatory to wash the folds of the outer ear, the folds of the nipple, the folds of the vulva (including the clitoral folds), and the anal folds during ghusl janabah (obligatory ritual bath), while removing any waxy, greasy, or sticky residue from them, and is rubbing (dalk) required for that? And does the discharge of pre-seminal fluid (madhy) during ghusl janabah affect its validity, or does the insertion of a finger or water into the anus during ghusl or fasting affect its validity?

In ghusl, the entire body must be covered with water, including the cartilages of the ears and the folds of the vulva. Overcoming doubt is sufficient for this; certainty is not required. Oily secretions are not considered a barrier. Rubbing the body is not obligatory in ghusl according to the majority of scholars. Madhy (pre-seminal fluid) nullifies wudu but does not invalidate ghusl. The impurity exiting from the private parts must be washed after its discharge ceases. If you doubt whether what exited is madhy or vaginal discharge, you have the choice to assign it whichever ruling you wish. The area between the buttocks must be washed, but inserting a finger inside the anus is not prescribed. There is a difference of opinion regarding whether water entering the anus invalidates fasting. You may adopt the easier opinion as long as you suffer from obsessive-compulsive disorder.