Thanks for using Sitefinity!
Please try to remove and re-add your templates. They are using master pages correct? Also why did you change the project name?
There are no templates in the project.
We would like to have on the same servers (IIS & SQL) a mirror of a project.
This would allow for developing against the live code base, without introducing instabilities in the live site.
"I have updated the sf_page_node.app_name to the new project name as well"
You shouldn't need to do this at all, perhaps that's where it's coming from. I've mirrored lots of sites, and pulled prod local, pushed live, etc etc.
The only thing you need to change is the data.config...and make sure the "playground" site in IIS points at the playground folder.