Several aspects of the OP's story trouble me. And believe me, i sympathize with him and hope his repairs are done ASAP.
First, the idea that the body shop would do mechanical repairs. The last time I had an accident that required both body work and mechanical repairs, the body shop sent the car back to the mechanical shop (same owner, franchised dealer), and it was done correctly. I had a previous accident repair done many years earlier in which the body shop tried to do the mechanical repair on brakes themselves -- I was nearly in an accident driving out of the shop when the job was (supposedly) done because the brakes did not work! So I would never again want a body shop to do mechanical work. That is not their expertise.
Second, the supply chain issues with Tesla's spare parts are becoming altogether too common. It seems as if this should have gotten sorted out by now. Model 3 will make the problem far, far more challenging. I am beginning to doubt Tesla's ability to scale up their service operation to match their sales success.
And third, the notion that so many parts had to be replaced seems bizarre, as others have said. This is the toughest issue to be sure about, not knowing enough about the damage and the Tesla design. But it sounds as if either the design is too fragile, or the repair guidance is too vague, or the body shop (certified or not) is either misinterpreting or taking advantage. I have certainly had many, many suspension and steering parts replaced on my many cars over the 48 years I drove before I got a Tesla (admittedly from corrosion or wear/tear damage, not from a collision), and I do not ever recall any one repair involving so many seemingly unaffected but connected parts. I hope this is a fluke and not a trend.
