Pirate Campaign

My players have been watching One Piece recently, and conveniently, I have been re-watching Black Sails. So we're doing a pirate campaign! We're not taking it too seriously, or trying to replicate the One Piece show, but I'm being relaxed on the crew rules of a ship, typically "ships" are manned by 5-10 people as crew, this lets me be a bit inventive with the captain, Boson, crew mates etc, and actually have characters on ships rather than nameless crew.

I'm creating a pirate faction called The Bloodline, yes this is WWE inspired. We have the following, and I've filled in what I have so far as crew (I'm keeping enemies/monsters as per monster manual to help me with roll20 and save time prepping);

Roman: Captain
Solo Sakoa: Quartermaster/Romans right hand man. He is a Mage (CR8), however have swapped out cone of cold and fly with Steel wind strike and Wall of force)
Tonga Loa: Assassin (CR8)
Jacub Fatu: Berserker Commander (CR8), the muscle to do Romans bidding
Jimmi and Jey Uso: Twins, Gladiators (CR5)
Tala Tonga: Big dumb guy, does what he's told, which is usually "smash that, kill that, stop that"

I'm not sure what stat block to use for Tala Tonga, just a big guy who either stops something/someone or hurts it, and for Roman, who ideally is a bit of everything, as captain stronger than the others, has some use of magic, good AC and magic defence. I'm not talking overpowered with Roman, but as captain, he should be worthy of respect of the rest of his crew. Any ideas?

FYI, players are currently level 3, they are not fighting these any time soon for obvious reasons. But there may be a show of power or demonstration as to why they are feared, and I like to keep things consistent and have the stats planned for later. Ideally, the party learn that taken them on crew vs crew will be a horrific idea, they need to take out each guy separately or at least when they are reduced in numbers greatly.

And p.s. yes the players are searching for a treasure that is rumoured to turn the owner into the king of the pirates, I've called this treasure "the Ninth". 

The big dumb guy could just be a Tough Boss. Also keep in mind that 5.5e Monster manual includes Pirate, Pirate Captain, and Pirate Admiral out-of-the-box if you don't want to homebrew the crew.