They have similar builds, but more so they basically do the same thing. From what Final Fantasy artists I know they told me learning Squall and Liguna (I think that's how you spell his name) makes it so drawing lighting is as simple as what stance her weapon is in. And ya they all fight in distinctive ways but an action shot is easy to just pick witch one you want. A more extreme case is fang and kain in the same bubble of final fantasy they both jump and slam down so just pick witch one holds the pointy stick and your good to go. But that's just what I've been told from the artists I know and ya a sample size of 2 isn't big I admit. Apparently it's just the stance and position of the body that makes the biggest issue weather or not the characters look the same is not a problem. With all that said if some artists wants to correct me and call me uninformed I will admit ya I'm not an artists personally so I simply take who I know for their words at face value.