Does Allah permit the rape and humiliation of a devout Muslim girl, or does divine justice necessitate her deserving of that? And does Allah permit the occurrence of humiliating calamities to a devout person, or is there a limit to trials?

All-Majestic Allah is the King and the Regulator of the universe. He decrees what He wills and judges as He desires, and there is no repeller of His decree. He has made this life a realm of trial and test, wherein He tests whomever He wills among His servants, even the prophets. In this, He has profound wisdom. A trial can be a punishment for sins, or for elevating the ranks of the patient one who is tested.

Accordingly, Allah may test a believing girl with what is mentioned in the question. Will and decree can refer to the universal, predetermined aspect, or the religious, legislative aspect. Allah permits what is mentioned from a universal and predetermined perspective, but He does not permit it from a religious and legislative perspective. A Muslim should be concerned with asking about matters that entail action.