Bartleby would be a bit confused by Opal. He never saw a human spit out flowers or shiny rocks before. He would need to know what Felix hunts before he decides if he likes him or not. He'd probably like Fred. He just wants to meet all different kinds of humans.
Hook will love Opal. She could provide him with loot and access to royalty. It's a pirate's dream. He would like to meet Fred and Felix too. Just to see if they could be of any use to him.