Is it totally from the ground up? or is is taking an existing Camaro and doing a lot of work to it?

From that engine photo shot in the article the firewall and cowl look very stock, as well as the fender braces. The heater/AC controls are stock looking too. I also think they are the controls for the non-AC version too.

Ahhh, OK, after reading that article again there was one word I overlooked, rebuilt.
And so Foose and Unique have joined forces to create
limited edition turn-key 1969 Camaros, essentially “new”
musclecars rebuilt from the ground up with the latest
suspension pieces and crate engines.