In several kingdom questlines, older characters make an appearance: Emperina in Glacial Peaks, Raven in Dragon’s Claw, etc.
It’s possible, though unlikely, to get to Glacial Peaks without ever opening Khaziel, or Dragon’s Claw without getting through Mist of Scales. What happens to the questline in those cases? Does Tassarion banter with himself? Does Visk place far too much trust in the hero?
i dont think the quest contents are interactive that way 
but the idea sounds fun (yet unrepeatable, you would have to have a ‘repeat quest line’ feature or it would force ppl to reset account/start anew just to see its different development - thats bothersome)
for now you can safely unlock them all in whatever order and also complete all the quest lines in whatever order without any loss on the roleplaying experience 
I can’t test it but I would’ve assumed you cannot start the questline in Dragon’s Claw without having finished the one in Mist of Scales etc. The second part of Khaziel cannot be finished without having finished Adana, that I can confirm.