Ambitious project you have there!

The hinges you are referring to are, at least in my experience, a two-piece affair.

There is a piece that is attached to the chassis, and another corresponding piece to the door.

My biggest concern is that the attaching points for dog legs might not be compatible with the other style, even if you were able to source them.

 

As someone who takes apart numerous models for interior improvements and exterior painting I have to say 'rather you than me'.
Better quality door hinges have either screw mounting posts or recesses in the bodywork.
And a matching setup in the doors, behind the cards.
If you feel it's worth a try, go with my best hopes for success.....

 

Yeah, this might be too lofty of a goal, especially while I still have a day job that takes up all my time.

I just see these Youtube vids where they make 1/64 diecast cars from no opening to full opening from scratch and I wish I could do that kind of thing. 1/18 seems like it would be much easier than working with tiny 1/64s.