No. It is the seed of a water lily, grown in ponds in northern India, then dried and heated until it puffs up. "Fox nut" is just the English name it picked up. Anyone avoiding tree nuts is not avoiding this.

This is raw makhana, sold plain and unroasted. Raw, it is soft and slightly chewy rather than crisp. Most people roast it before eating, which is when it becomes light and crunchy. It is sold in its raw state so you can season and roast it as you like.

Preferably yes — a little roasting is the usual way, though it comes down to personal preference. A few minutes in a dry pan, or in a little butter or oil, until it feels light and crisp. Season while still warm so it sticks.

Almost anything, since it carries flavour rather than competing with it. Salt and pepper, chilli, smoked paprika, cinnamon and sugar, or grated hard cheese all work. Treat it the way you would plain popcorn.

Raw makhana is soft and chewy to begin with, and roasting is what makes it crisp. That crispness does not last in open air, so move it to an airtight container once cool. If it softens again, a few minutes in a low oven brings the crunch straight back.