So, I didn't read the thread but I wanted to point out something really important that not a lot of people know.
My aunt works in the government in one of the Mexican states and personally told me that the dealt with the caravan by funding buses to wait for them at the beginning of the state border and transport them to the next.
She told me this because I specifically asked her how they handled it when she came to the U.S. to visit for a week last summer.
(Being in the government and "upper class" in Mexico, they (my family) get to travel back and forth and are trusted to not stay here in the states because their lives in Mexico are so luxurious. It's actually good for our economy since they buy a lot of American brands to take home with them...anyways...)
The reason was that they didn't want a trail of trash and violence in their state, which is known for being really beautiful and full of nature.
From what I know, her state is the first one to have done that after seeing the results of the caravan moving through the more southern states, and it's very likely that other states followed suit.
Their buses didn't take them all the way to the U.S. border, since their goal was to avoid littering and violence (a lot of it being from cartels, but also just the general increase in violence with two cultures colliding), they only took them to the next state line.
So with that said, if you see that when approaching central Mexico, the migrants started taking buses, it's because the Mexican states knew that their final destination was the U.S. and figured it'd save them more money in the long run to get them out asap.
They didn't want a huge population of outsiders moving in more than the U.S. does, in fact, they probably want it even less than the U.S. since there's a lot of liberals here want to allow ever person in. Mexico isn't liberal in that sense at all.
They have enough issues with the cartel and a seedy government (in some states) working alongside of the cartel; they really do not want to deal with additional immigrants adding fuel to the fire.
Plus, the caravan wouldn't have started to move through Mexico to begin with if the destination wasn't the U.S., so Mexico saw it as something the U.S. has to deal with anyways.
I personally thought it was funny when she told me what they had done, after months of hearing that this was all some conspiracy because the migrants took buses, it was hilarious that she replied to me so nonchalantly, like "Oh that, we put them on buses so they wouldn't leave trash, it wasn't too bad".