Kudos for your research and links.
The fact remains that Texas and the lands to to the West were ceded to Texas from Mexico by treaty. The Republic of Texas later sold or gave the lands further West to the US.
Mexico has no legal claim on any of that land.
They don't let facts get in the way. All across the West and on University campuses are folks who are absolutely certain that the land under their feet belongs to the "brown race", and that there will be no justice until their dream is realized. Their dream involves the death or expulsion of those that don't have the correct skin tone.
Mexico has no legal claim on any of that land.
They will claim those lands by right of reconquest, that is the plan, they moved in Americans moved out ergo the lands now belong to Mexico.
Illegal aliens are an invading army with no right to be here or claim citizenship in our country for them or their children.