The questioner says: if he only wipes over the area above the ankles (when wiping over the khuff), will this be sufficient?
It’s not sufficient; because he did not wipe over the area which the Prophet ﷺ wiped; (which is) the surface of the Khuffs, i.e. the surface of the feet. But this person has wiped over a different area. He is considered to have wiped over his shin. Therefore, this wiping is not sufficient, according to the people of knowledge, because he wiped over a different place.
Also, if he wiped his heels alone and did not wipe on the surface of his two feet, it will not be sufficient, according to the people of knowledge.
Similarly, the correct position is that it’s not sufficient if he wipes the underside of the khuffs alone; if he doesn’t wipe the surface of the khuffs and only wipes the bottoms, it’s not sufficient, going by the correct ruling from the statements of the people of knowledge.
What if he inserts his hand into the khuff and wipes from the inside, will this be sufficient for him or not?
It’s not sufficient; because he didn’t wipe the area which the Prophet ﷺ wiped. What’s more, this person is contradicting the Sunnah; and the Prophet ﷺ said: “Whoever does an action, which we have given no command for, will have it rejected.”
Shaykh Muhammad ibn Hizaam – may Allaah preserve him
Abu Abdillaah Ja’far ibn Abdillaah ibn Zubayr Al-Makeekee
Also see: How do you wipe over the socks?