Maybe I have terrible eyes, who knows, but in the video for those last two tweets the sphere looks off. Like the shading or shadow of the lower portion looks so fake to me. Again, low quality video and who knows what kind of graininess is being added by twitter...but something just strikes me as off.
As TC said, who knows how valid, but I have a hard time trusting the claims by the Mexican university. Here is just a little of my non-expert video analysis. Much like instant replay in sports, I could be biased by skepticism and others may have different takes.

In the first part of one of these videos they show this man walking up to the sphere, and it's in the middle of trees. Later they talk about when people returned to where it landed the grass was dead, but there are no trees that I saw.

Also, there is another video angle of that guy walking toward it, which makes me wonder if there was a 3rd person videoing at the same time, or if the person recorded him doing the same thing twice.

I also think the sphere looks bigger in the video with the guy walking down to it than it does in the videos from the lab testing, comparing the sphere in this last photo to the 1st one I posted. Granted that could be an issue with video perceptions or something

I don't have much to offer on the engravings or findings of fiber optics and stuff, but it all comes across as hoax to me. Maybe more will come out. I do find it interesting that we had that other video of the guy filming the helicopter. Completely different parts of the world, so I hope we can get some more to study or talk about. I have no idea how hard (or easy) it is to fake something flying around like this.