If only Mihawk and Croc joined him then Crocodile's ranking strength wise has to be pretty high, could have gotten strong as shit with haki + sand and awakening.
+ he gained a new crew/following which also adds up to the organisation. Buggy and Crocodile I assume are responsible for keeping a fuckton of money/gold flowing so they can use the bounty system against the marines too, perhaps Captain Johns treasure + Crocodile's mafia