Sure, I'm OK with not doing an arranged marriage. Perhaps they meet when they both decide they've had enough of their fathers' control and escape to a different region? Or perhaps they've already escaped but lost their fathers in the process, and travel somewhere else to recover? I've been entertaining the idea of having Athrun abscond to Alola with his inheritance after outing his father as a member of Team Galactic/Plasma/Flare and helping Looker arrest him. And then they can end up taking the Island Challenge as they do some soul-searching and coming to terms with their lots in life.