1) The pure “mind” devoid of incoming defilements is not belonging to the five aggregates, and it's not the mind at the mundane sense.
"Luminous, monks, is the mind. And it is defiled by incoming defilements. The uninstructed run-of-the-mill person doesn't discern that as it actually is present, which is why I tell you that — for the uninstructed run-of-the-mill person — there is no development of the mind."
"Luminous, monks, is the mind. And it is freed from incoming defilements. The well-instructed disciple of the noble ones discerns that as it actually is present, which is why I tell you that — for the well-instructed disciple of the noble ones — there is development of the mind." -- AN1
2) “The word 'insight' is an unfortunate as well as an ironic coincidence. When we say insight we mean/imagine some conceptual understanding. The Buddhas original terms were 'nana' and 'dassana'- to know and see.”
--But we first have to learn and understand it correctly (to obtain right view) before we can see/experience it.
3) "So, where is nibbana? If there were no arahants, where is nibbana?"
--"The Buddha also refers to Nibbana as a 'dhatu,' an element, the 'deathless element' (amata-dhatu). He compares the element of Nibbana to an ocean. He says that just as the great ocean remains at the same level no matter how much water pours into it from the rivers [the unconditioned, the pure "mind" of arahants], without increase or decrease, so the Nibbana element remains the same, no matter whether many or few people attain Nibbana.
Metta to all!