The best way to approach an overhaul is to sneak up on the car quietly with sawzall in hand
Seriously though, after significantly "reconstructing" a 7 to fit a new drivetrain(Olds small block to LS1), I think we(Mazda and I) would have been ahead by starting from scratch and using the existing car for simple dimensional references.
The Rotus we started with was not exactly a gem in terms of fit, finish, and overall condition, so there was little remorse in cutting it up. With a car that appears as clean as yours, I would do my best to avoid major reconstructive surgery. It may sound like a broken record, but there are better platforms for what you propose.
Just my $.02