"10-days contract" is a special type of contract, with a set of other rules such as can only renew it once, after then either sign for the rest of the season or byebye. It is not allowed to sign players to "10-days contract" until Jan.5.
Dee Brown wasn't with a 10 days contract, it was another type of temporary contract, but according to league rule, all such contract becomes guaranteed after Jan.10.
We r above luxry tax threshold, although we have 3 open roster spots, only one will be used. And Kerr will do everything within the rule to avoid signing him to fully guaranteed contract until the very last deadline (in March?). Unless, an ideal target fall in our hand.