Not seen a chief rigger feel for 'bruising' in years! I certainly never managed it on anything more modern than a Gnat.
As the Phoenix is a one off, accuracy isn't over critical, you just make the bits fit and the box frame design is simple, strong and practical. Only really exotic materials in an aircraft are in the engine and avionics, so the ship's workshop should have all the gear to weld it together.
So, yes, the Chief has all the wotsits to make a Viper.
Nor was he aiming to create the ultimate fighting machine, or anything particularly special. The project and meaning grew as people realized he meant to create it. Funny how people climb on a bandwagon when it starts to look a success?
The virus turn actually made some sense for once