Do not change road hierarchy at random. This is a motorway. It is officially designated as such and it is physically so.

Aquí cambiaste parte de lo que no es autopista a autopista. Fíjate en http://gaia.inegi.org.mx/mdm6/ antes de etiquetar a una autopista.

Do not change road hierarchy at random, especially in countries you are not familiar with.

La parte de la 15D que va dentro de Santa Ana no es autopista, pues no tiene restricción de acceso.

I added water=coastline to the lagoon.

JOSM warns about overlapping water. You should file a bug report with them.

My understanding is that “water=lagoon” is precisely for this situation. The main reason for my change is to add the name for the lagoon, which can not be done if it is just “water=coastline”. Do you recommend that I add “water=coastline” too?

In OSM, usage of the hierarchy inside urban areas is different from outside areas, that is in most of the world. Just taking a look around the place you edit, in the map, will tell you that.

The wiki is very general. In Mexico and in particular in this area, highway=tertiary is used for linking smaller towns, villages and borough.

Again, do not change hierarchy at random, especially in a place where you are unfamiliar with its well-established conventions, per community. Reincidence will result in being reported.

Do not change the street importance levels at random. You changed “tertiary” to “residential” for the main road of this borough.

Probably a JOSM bug. I removed the tag now.