Praise be to Allah.
The four madhhabs are agreed that one of the conditions for wiping over the khuffayn is that they should cover the area that must be washed (in Wudu) – the ankles as well as the feet. If they do not cover the ankles, then wiping over them is not valid, by analogy with Wudu. And because what appears must be washed and what is covered must be wiped over, it is not possible to combine the original rule and the alternative in one limb.
See: Sharh Mukhtasar Khaleel by al-Kharashi (179); Haashiyat Qalyoobi wa ‘Umayrah (1/68); al-Mawsoo‘ah al-Fiqhiyyah (37/264).
There is no scholarly consensus concerning this issue; rather there is a difference of opinion among the scholars (may Allah have mercy on them). Some of the scholars regarded it as permissible to wipe over the khuff even if it does not cover the ankles; this is the view of Ibn Hazm and was narrated from al-Awzaa‘i. Other scholars disallow that, as is the view of the fuqaha’ of the four madhhabs.
It says in al-Mughni (1/180): He should not wipe except over the khuffayn or whatever takes their place, such as those that are cut down, and the like, provided that it goes further than the ankles. What that means – and Allah knows best – is anything that takes the place of the khuffayn in covering the place that must be washed, and in which it is possible to walk, and it is firm by itself. The one that is cut down is a short khuff. It is only permissible to wipe over it if it covers the place that must be washed in Wudu, and does not show the ankle because it is tight or tied. This is the view of ash-Shaafa‘i and Abu Thawr. But if it is cut lower than the ankle it is not permissible to wipe over it. This is the correct view narrated from Malik. It was also narrated from him, and from al-Awzaa‘i, that it is permissible to wipe over it because it is a khuff in which it is possible to walk and is similar to that which covers. But in our view it does not cover the place that must be washed, so it is more like a slipper or sandal. End quote.
Ibn Hazm (may Allah have mercy on him) said: If the khuffayn are cut below the ankle, then wiping over them is permissible. This is the view of al-Awzaa‘i. It was also narrated from him that he said: The muhrim (pilgrim in ihram) may wipe over the khuffayn that are cut beneath the ankle. Others said that they cannot be wiped over unless they come above the ankle. ‘Ali [i.e. Ibn Hazm] said: It was narrated in a saheeh report from the Messenger of Allah (blessings and peace of Allah be upon him) that he instructed people to wipe over the khuffayn, and that he wiped over the socks. If there had been a specific limit, he (peace be upon him) would not have omitted to mention it. So it must be the case that anything that can be called a khuff, sock or any other footwear that covers the feet may be wiped over."(Al-Muhalla 1/336).
The fact that the four madhhabs agree on a matter does not mean there is consensus on it, and the fact that the Rightly-Guided Caliphs agreed on a view is not to be regarded as consensus, so in the case of anyone of lesser standing this point is even more apt.
It says in Madhkirat Usool al-Fiqh by Shaykh Muhammad al-Ameen ibn Mukhtaar ash-Shinqeeti (may Allah have mercy on him): It is not regarded as consensus if most of the scholars of a given era agree upon some matter, according to the majority of scholars. Ibn Jareer at-Tabari and Abu Bakr ar-Raawi said: For one or two scholars to have different views does not undermine the consensus of the scholars. Ahmad (may Allah have mercy on him) agreed with this point, but the majority of scholars stated that what matters is the view of all the scholars of the ummah, because infallibility belongs to all (when they agree on an issue), not just some. The argument for the opposite view is that the view of the majority should be heeded and the view of the minority should be overlooked."(Madhkirat Usool al-Fiqh 1/156)
It also says:
The agreement of the four caliphs does not constitute consensus according to the majority. The correct view is that it constitutes evidence, not consensus, because consensus can only occur if all are agreed.
And Allah knows best.