Don't know if they're weevils, they're tiny brownish beetles (the dark dots you see in the front, for example).
No more pictures because I threw it away before they could spread to all of my kitchen. It looked like they couldn't leave the jar, so hopefully they didn't.
No idea, this jar was laying around for months, I only rarely use it. Maybe I left it open recently
Eggs got mixed in with ground spice and they've just now hatched?
Yeah most likely this