OH I LOVE THIS QUESTION SO MUCH! This is something I've thought about deeply. Its a joint effort but some of their kids gravitate towards a certain side more than others, but in general: Roku tries his best to incorporate as much of his culture with their kids as much as possible, traditions, etiquette, beliefs, but unfortunately another large portion of it can only really be practiced within the Ocean or near beaches. He actually does his best to take them to the ocean as much as possible, and tries to make trips to the ruby sea especially even if aymeric isnt able to join them, and there they are able to learn more of that side of their culture when they visit. By default though, its easier for them to primarily grow up Ishgardian. Yūna, for example, leans more into Ishgardian culture than anything else, but one of their other sons takes a lot of pride in Roku's side and wears more traditional clothing and follows that more than his other siblings. It's not something that either one of them will do on their own, Roku (though he doesnt really adhere to ishgardian culture that much) does take steps in learning it specifically to help Aymeric teach their kids, and vice versa. Maybe a little off topic, but this goes for Au Ra specific care as well. Roku has been quite open about scale care for example, and Aymeric does assist him with it so hes not entirely unprepared when their kids end up needing help as well. I imagine they read up on both Elezen/Ishgardian, Raen/Sui-no-sato culture/childcare a lot as well. Theyre both the type to want to be as prepared as possible. Im going all over the place now but another good example is how Yūna is very obviously not an Ishgardian name, but its something both roku AND aymeric decided on together taking ideas from each other and their culture and agreeing on what fit best. Theyre very open and honest with each other so even if their respective cultures are vastly different they work together to figure out how best to give their kids that knowledge and allow them to take steps in exploring either (or both!) Paths for themselves!