Hi Botanical_Bryce,
Good question. I too continue to be confused by so many local names that happen to also confusingly exist in other regions for different bananas. It gets worse when they belong to e.g. the same sub-group, like "Silk," with minute differences among them. And I can't rely solely on the linnaean system for clarity, as I've found.
The two bananas you talk about are indeed different ones.
Lacatan from Latin America
As you write, I understand this to be a AAA Cavendish cultivar as well.
It is also available in the Philippines, where it is known as "Bungulan."
Lakatan from the Philippines
Again, as you write, this is an AA cultivar and also considered to be by many Filipinos to be the "best tasting banana in the Philippines."
To confuse matters, the Lakatan can also be spelled as "Lacatan" in the Philippines, but obviously only referring to the AA Lakatan.
Why are there spelling versions of words with with C substituting for K in the Philippines? Well you'll have to consider the historical Spanish impact over there and the subsequent spelling changes that occurred over time. As you may know, under Spanish spelling conventions, the hard C sound is simply spelled with a C, similar to the C sound in the English word "car." However, under the Filipino system, there is in fact no C, only a K. So during Spanish times, the convention would have been for Filipinos to have spelled the Lakatan as "Lacatan," or for that matter, any word with a hard C sound with a C.
Gradually since independence from both Spain and the US, the increasing incidence of the use of the Filipino letter K has meant that a number of Cs were changed to Ks in words,
but confusingly, not in all instances and in some cases, I believe both are accepted! So if you see a Filipino word spelled with a C, it harks back to the days when it was a Spanish colony.
Anyway, I hope that helps.
The one best site I found that explains the taxonomic side of things as I understand it is
https://wikivisually.com/wiki/Lakatan_banana
The language explanation? Well, I was born in the Philippines and so this is part of my general understanding of how things have changed over time there.