Secret Badges?

I can’t find how to get these badges. If you know can you tell me.

I have two unclocked…The crossed bones and bone clubs with spikes… My friend has the bone clubs and crossed machetes…Have no idea how we got them.

People are saying they are unlocked by 3 starring someone’s elite skill/weapon. Not those specifically, of course, just that they can be unlocked in that fashion.

Ive got three of em unlocked but only 2 elites that couldnt possibly be how there unlocked