Is tying the hair in a bun under the hijab considered among the heads like the humps of camels, and what is the ruling on wiping over this tying, and is it permissible to adopt the opinion of one who does not mandate wiping the entire head for a woman?

As for the act of what is called "al-ka'kah" (a type of bun or hairstyle): its ruling is explained in Fatwa (definition): 125891. As for a woman limiting herself to wiping only part of the head (during ablution): there is no harm in it, and it is a strong opinion, as stated in Fatwa: 120882. Therefore, if you wipe your entire head, it is more cautious. And if you limit yourself to wiping part of it, following those who permit it, it is permissible, whether the hair is styled in the aforementioned manner or otherwise.