Oh man. I have no specifics... but I have general ideas. Very general. >__>
Vlad and Helena would go off traveling the world for an indeterminate amount of time. Then they would find a place to settle down somewhere - Vlad would probably prefer to live in Europe, but who knows - and a few years down the road they'd end up getting married. Kids are debatable, because it depends on how persuasive Helena is. >__> But if they did have kids it'd bring out this side of him that he never even thought existed - especially if they had a girl. Oh god, he'd spoil her like crazy and then deny it. But he'd like a son too. :D (DES CHIME IN WITH ANYTHING YOU CAME UP WITH TOO. XD)
Bran... I don't know. It'd depend on how things go with Gabby after they spend some time in Georgia with her family. So I'm gonna come back to that. If he did end up alone then he'd probably go off to France and spend the rest of his life making music. Woo.
Hannah would stay in New York for a while and finally enroll in college. Then she'd end up working her ass off in order to put herself through veterinary school, but she'd graduate with good grades and would start working at a veterinary practice downtown or something. She'd adopt more pets over the years and would probably end up marrying another animal-lover at some point - her very own Prince Charming. Kids are... a possibility, but they'd definitely have tons of animals.
And then there's Cole. In a perfect world I'd say he and Illy travel for a while, see America, then eventually settle down and get married. Possibly have twin girls. But LOL WHEN HAS ANYTHING EVER WORKED OUT FOR COLE. So I'm just going with 'no comment' for him atm. >__>