Lets think Hidan the Jashin ("Evil God" or "Evil Heart") religion guy who doesn't fight before praying , is the slowest attacking Akatsuki member who uses the three-bladed scythe that he can use as a throwing weapon while retaining control of it with a thick rope wrapped around his wrist. Also his religion thinks slaughter, and where anything less than total destruction is considered a sin.
Kakuzu has a great amount of physical strength , He even refers to himself as the Treasurer of Akatsuki , because he's incredibly greed-driven , and evnis a bountyhunter. So who do you believe is 3rd , because so far the list in order making sence.