Is the ruling of the detestability of using water heated by usurped means the opinion of all four Imams, or only Imam Ahmad? And is adopting the other narration from Imam Ahmad, which permits it, considered following dispensations?

Only the Hanbalis explicitly stated the detestability of what has been heated with usurped property. The second narration from Ahmad—which is that it is not detestable—is more preponderant, and it aligns with the view of the Hanafis, Malikis, and Shafi'is, while the usurper remains sinful. Adopting this view does not fall under the blameworthy seeking of dispensations, though refraining from it out of piety is good. Purification with it is valid in all cases, and there is no sin in it. At most, it is considered detestable, and one who commits a detestable act is not sinful, while one who refrains from it is rewarded.