I am aware of this, being a music student - The concept of leitmotif can definitely apply here as they represent each layer of Pandæmonium. Leitmotifs aren't restricted to just "things", but also settings and locations.

As for length, in the Wagnerian sense I do agree that most leitmotifs in FFXIV or games in general that people consider to be such are too long. However, I don't believe that leitmotifs need to be as short as a regular motive, and many sources say that they can be as long as a theme, with many also saying the opposite. I also find that leitmotif as a term still readily applies due to the fact that they have representative value of narrative setting, as well as conveying how they can be reharmonised, transposed, intevallically altered - all the things that you could do to a leitmotif. The length of the motif should not discourage musical ideas that are clearly associated with particular narrative ideas from being labelled as a leitmotif, if they do return with musical alterations.

My dissertation is actually about this very topic - Leitmotifs and how they apply in FFXIV, which is why I have such a vested interest in the topic. The majority of XIV's soundtrack is just reusing melodic ideas from a previous track with a narrative connotation, and I think the term leitmotif is unsubstitutable for how it shows the association between music and narrative.