Not at the moment, the problem is that the total project is quite large and would require me to write quite some documentation if you wanted to get started. Once I free up some time I might!
As far as I know, his family did speak it never passed it on, so he learn it afterwards. So semi-native, I guess. The variant is a central one, relatively close to the variant that would have been spoken by the Mexica.
People have devoted their entire lives to studying this, but I can give a very short overview:
First, there's early colonial maps, such as the Mapa de Uppsala, which give us a decent understanding of the city.
Then there are the accounts of the arriving Spanish. There's also archaeological evidence all throughout Mexico City, though much has been actively destroyed.
A bit of artistic license, but the trees play a crucial role.
They are Ahuejotes, and they keep together the plots of farmland called Chinampas.
You can see some of this today in Xochimilco.
We don't know if that was what it was like in Tenochtitlan, but it is likely. What adds to this is the fact that the houses are all one story, so the trees look taller and more numerous than they are.
If you have any questions, feel free to ask.
The question I always get from tech people - yes, all open source software.
90% Blender, 9% Gimp, 1% Darktable or so.