Is it necessary to lift the hair to wipe the whiteness between the head and the ear during wudu' if the hair is tied and covers that area, or is it permissible to wipe over the hair that covers it? And does wiping the outer part of the ears include only the curved part of the ear, or must the movable cartilage be wiped, and what is the ruling regarding the back of the ear?

The white area above the ears is considered part of the head, and this is the correct view within the madhhab (school of thought). Wiping over it is sufficient, even if it is covered by hair. The entire head must be wiped, and this is the more cautious approach. As for wiping the ears, it is a Sunnah according to the majority of scholars. However, the adopted view among the Hanbalis is that it is obligatory because they consider the ears part of the head. It is not obligatory to wipe what is hidden of the ears by the cartilages, but only the visible parts.