Treno's Easter Egg

So Treno has an easter egg I didn't even know existed, but was discovered by a big FFIX enjoyer I know. There's a Milalla standing near a cage with a coin in it, saying 'That's one... but where are the other 12?' which is apparently a reference to FFIX's version of Treno, where you can collect the 13 Stellazzio coins to get a reward.

However, we both hunted around and could only find 12 of the 13 cages, all of which are in the Treno map.

Has anyone else seen them, or found all 13? And where did you find them?

I haven't found all 12 myself, but as far as being able to find the 13th (Ophiuchus) if you remember it's in the same place as Scorpio in IX so of course you can't find all 13 - the 13th is hidden in a way that can't be replicated since the XIV Stellazio coins can't be collected (or interacted with in any way). IX's Stellazio coins were also scattered across the game world, not just Treno, but you turned them in for rewards there.