Actually it makes sense to assumed there is 2 indie. Fujitora is indie (already proven)
That left Sabo, Law, Luffy, Cavendish. Law and Cavendish are problem to be mafia.
Luffy is mafia as well. He is outsider and he opposes Doffy.
That left Sabo. He is outsider but his goal is mera mera not to defeat Doflamnigo.