Dye and Mehndi

Using black dye

Q: Because of the colour not catching the hair, is it permissible for a person to dye the hair black and later on (few hours later) go over the black dye with another colour?

Mehndi patterns

Q: Is the way of putting hennah patterns of flowers and shapes etc. on our Muslim sisters hands and feet which are seen in public correct in connection to how it was used by women in the time of our Nabi (sallallahu alaihi wasallam)?

Using black dye

Q: When explaining the maslah of Khidaab, my teacher said the following (In his own words):

Within Ahnaaf, there is two qowls on whether you can do black khidaab for beauty (zeenat)

1. According to some, it isn't permissable at all, it is haraam.

2. A lot of muftiyaani karaam and people of fataawa have given the fatwah of jawaaz. (This is excluding the situation when an old man has married a young women, because in this situation it is permissibile to do black khidaab, and this is the qowl of nearly all the fuqahaa).

My question is, do the Hanafiyah actually have the second qowl mentioned above? From what I have read on your website and ask imam, black khidaab isn't permissible. He also mentioned that Allahmah Ibnul Qayim has wrote a list of the Sahaabah radiyallahu anhum who would do black khidaab in zaadul ma'aad.