Of course, since these models are freely available, you can easily upload the project with them on github. By the way, you have a quite interesting project, thanks for sharing it :)
Viewing post in PSX Industrial Environment Asset Pack comments
I’ve been posting my findings in devlogs and as it turns out an atlas texture gave no visible improvements, to my surprise. Scaling down textures had no impact either. The only other thing I haven’t tried is LODs which will have to be made by hand for Godot 3 as it doesn’t generate them automatically AFAIK