What is the ruling regarding what is discharged after a husband's phone call, and what should a woman do if she is unsure about the nature of the discharge (is it madhiy or maniy)? And is it obligatory to make up missed prayers due to these doubts, and in what order? And what is the ruling regarding kohl under the fingernails during ghusl?

What you mentioned in your question about the obsessive thoughts that lead to delaying prayers without a legitimate Shar'i reason, you must ignore them. Not everything that issues from a woman is semen (mani), so ghusl (definition) (ritual bath) is not obligatory unless it is confirmed to be semen. As for kohl under the nail, if it is merely a color, it does not harm; but if it has a physical mass, scholars differed concerning it. Regarding making up missed prayers, some scholars held that it is obligatory to start by making up the missed prayers before the current prayer, and among them are those who said it is obligatory for a small number of missed prayers. The more cautious approach is to begin by making up what is easy for you from the missed prayers in their proper order, and if you fear the time for the current prayer will expire, then perform it before making up the missed prayers.