Does seunghyun know that he can marry yuta in America and that he does not have to "adopt"...

he probably wants to have smth thats legal in every country so that they can eventually go back home or travel the world together without any restrictions also i dont think he meant that theyll be immigrating to america its probably just a temporary visit so the marriage certificate wouldnt be valid in south korea/japan

Ohhh I didn't think of that, but isn't yuta an adult so can he be adopted