Marzban
Yes. Marzban is attested as a Sasanian and medieval Persian administrative title (literally 'border-guardian') and later used as a rare given name in Persianate contexts.
Marzban is cultural-historical rather than theological; Muslims in Persian-speaking regions have used it as a personal name. It is not an epithet of God and has no Quranic provenance.
It connotes guardianship, responsibility for a frontier or boundary, martial-administrative duty, and vigilance.
Yes. Variants and transliterations such as Marzuban and Marzaban occur in regional records and oral usage.
Common informal short forms include 'Marz' or 'Zban' in colloquial use, though these are rare; historically the full form is preferred.