How does it work for the other miners/addresses? Are you keeping their share of sats in custody until they reach the minimum payout? If this is the case one of the adresses from the coinbase transaction would be your custody address from which you would later pay out, right? 

 I’m a miner with that and that’s how it works 

 One address is ours for those who didn't hit the threshold yet.

There are multiple reasons for this.