Almost definitely. Although I guess if you really were worried about tracking Lupin specifically a marine would make more sense but haha Pops~ Then you'd be stuck following all their orders! :P

It pays depending what you bring in for bounties. Whatever bountied pirate you capture and turn in, that's what you get paid. If you're a marine you get a steady paycheck and I THINK there's bonuses for bounties but really I don't pay much attention to that sort of thing.