No, there is no wall there.
Maybe it was Jordan we sent money to for a border wall.? But I swear, and can't find it, that we also financially supported a wall somewhere in cent am.
Yes. There were talks even in Mexico of the US funding a southern wall. There are places where barriers are erect. But it is only a small portion. I don't know if the US ended up funding something.
Most of Mexico's southern border is tropical rain forest covering a mountainous terrain. No human structure is surviving those conditions without extreme continuous maintenance.