What is the ruling on the fasting of a woman who has reached menopause if menstrual blood flows?

If a woman reaches the age of menopause (which is usually sixty-two) and her menses have ceased, then she sees blood after that, and its duration is not less than a day and a night (24 hours), it is menstruation (hayd). If it is less than a day and a night, she is considered as having non-menstrual vaginal bleeding (mustahada), so she fasts and prays. However, she must perform ablution for every obligatory prayer after its time enters, pray immediately, and be treated as a person with a continuous condition. There is no specific end limit for a woman's menstruation; it is possible as long as the woman is alive. And Allah the Almighty knows best.

Is a menstruating woman obliged to pray during menses, and should she make up missed prayers?

All perfect praise be to Allah, The Lord of The Worlds                                                                                                                                                                        A menstruating woman is prohibited from prayer during her menses, and she isn`t obliged to make up missed prayers. And Allah Knows Best.

What is the ruling on a person who insists on praying in a specific spot and becomes angry if someone else prays there?

ruling on a person who persists in praying in a specific spot and becomes angry if someone else occupies it

Should nail polish be removed before making ablution?

Yes, it should be removed because it prevents water from reaching the nails.