Is gathering short hair when wiping the ears during Wudu considered valid, or is it an act of extremism, and is wiping valid with hair acting as a barrier between the hand and the ear, knowing that the questioner follows the Hanbali school of thought?

Your ablution is valid even if the hairs acted as a barrier preventing water from reaching the ear. And if you intentionally omitted wiping the ears, your ablution is still valid, because wiping the ears is a Sunnah (definition) according to the majority of scholars. Even the Hanbalis, who hold that wiping them is obligatory, stated that if one omits it, whether intentionally or forgetfully, their ablution is sufficient, because they are secondary to the head. Therefore, stop your excessive worrying.