A unique theory by
@HydraGen2299 that I am going to bring up here, but it would make sense if it is of unifying the three to be a trilogy of sorts.
As the Monstruos facades have taken place, they show differing sides of the Mausoleum. The original house facade, showed it from the element of those in poorer communities and those in smaller brackets. Monstruos 2; seems to step up it's architecture as a result, seemingly factoring into higher paying clientele as part of of those buried within the mausoleum.
If Monstruos 3 is going to follow suit, it might be possible that this is going to be in relation to that of the highest paying clientele to those who reside within the Mausoleum. More "Celebrity" and elite resting and laying their heads to eternally rest within the chambers and halls.
Could be possible that as the Monstruos trilogy occurs, we see it from the perspective of the tax brackets that identify that of each set of legends. And that as we reach the end, we might be seeing the most "Iconic" latin american legends take up residence as a result.