Is it permissible to perform Salatul-Istikhara for each university separately, or is one Salatul-Istikhara sufficient for a chosen university? And is it obligatory to repeat Salatul-Istikhara, or is one prayer sufficient?

Istikhara is not obligatory; rather, it is recommended when embarking on a matter where the correct path is unknown. It is permissible to perform it for each issue separately, which is preferable, just as it is permissible to perform a single Istikhara for several matters. It is also prescribed to repeat Istikhara more than once.