I'd say that the show is targeted to people ages 6-13. I'd start with 6, because that's when you really grasp the "good guy bad guy" concept. I'd stop with 13 because, well, it's technically a kids show.
For how they can get out, there is a legend that someone will come with the ability to command all Seven Seas. When the seas are united, then the Triangle will open. Nobody commands the Seven Seas. Clovis suggests in episode 1 that Zak could be the one who would eventually command the Seven Seas, but Zak disagrees, saying he just wants to go home.
As for Skullivar, I'd guess he wants the power to command the Seven Seas.
Welp, that's really all I have. Sorry if this wasn't very good.
Well i have been thinking for a long time that calabras is related to zak in someway. Because we don't know how he looked as human and he only seems to trust zak. He's always trying to give advise to him about how a pirate should act, as if he wants zak to follow he's footsteps...At least that's my theory.
I think it's aimed for the same type of audience as Miraculous, when it comes to ages, anyway. (ahem, even though I'm almost 16 and I'm totally obsessed with this show... xD) However, unlike Miraculous, I think Zak Storm is aimed more for boys. (once again, even though I'm a girl. ^-^) Yeah, I love the concept, too! :D Well, they've made it clear that they can escape the Triangle by opening all seven waypoints. I think they'll eventually accomplish that, but the real question is, what will they do after that? I don't want to see them go their separate ways. :( That would be sad. I'm not sure about Skullivar's intentions. He obviously wants Calabrass, and he mentioned something about a machine being ready in the beginning of "Trial by Fire." And that all the machine needed was the legendary sword, which is obviously Calabrass. Or maybe he just wants to get out of the Triangle just as much as the Seven C's do...?