Abelia: slow burn, you have to break through his shell of indifference to get at the sensitive shy interior, and help him stand up to his father and come to terms with the death of his mother.

Hibiscus: he's always friendly but you won't get his attention and unlock his route unless you max out your pokemon battling stat, you fail the route if he beats you but if you win the route officially starts, you have to beat him in a battle on every encounter and get to the root of his fear of stagnation.

Zephyr: easiest route to start, he'll be flirting with you the entire time, but he has extreme wanderlust, if you want to settle down in one place he'll still love you but he'll leave, the route is about living life to the fullest with the time you have together, then eventually learning to let him go until the wind eventually brings him back into your life.