Is there a sin incurred by not detailing the specifics of the theft to which students' funds were exposed, so long as the outcome is the same, which is theft?

Lying is forbidden. If a Muslim needs to avoid revealing the truth, he may resort to tawriyah (equivocation) and ma'areedh al-kalam (ambiguous statements), which involve speaking words that have an apparent meaning and another hidden meaning, with the hidden meaning being the intended one. You, the questioner, are permitted to use tawriyah provided that the money was not stolen due to your negligence, and that the tawriyah does not lead to the loss of students' rights. Scholars have explicitly stated that tawriyah is forbidden if it leads to taking what is false or denying what is rightfully due.