If there were to be Hawaii characters on the Sydney series, I'd want it to be Jane and Ernie, maybe Jessie. Lucy was my least favorite character from the Hawaii series. As for super-duper-ueber-agent Sam Hanna, hope he gets nowhere close to Sydney, already ruined Hawaii's final season.
I was annoyed
not by the lab created virus transmitted by remote controllable mosquito part - but rather the antidote/cure stolen-reclaimed-still in time part for Rosie while the bike-police-guy already bit the dust and Rosie seemingly rather easily recovered, despite not being infected much later. They also should have found a better way to include Rosie's wife passing away than him reacting this way and Blue telling him in the hospital.
Meh, Rosie is a tough old bird

And his exposure occurred some time after the police officer's.