I'm pretty confident he's talking about homages and stylistic callouts, despite the ambiguous wording.

Note how he talks about the Crystal Tower that they have plans to add; he's talking about visual and thematic inspiration from FF3, such that people who are fans of the game will be able to look at XIV's Crystal Tower and recognise it at a wide-scale, and go "oh huh this is like what that might have looked like in today's graphics", but that doesn't mean it's a copy-and-paste job of FF3's actual Crystal Tower.

I assume the same principle will hold, generally, throughout.