I don't know if this is done yet, or if it's even possible, but I want to know if it's possible to replace both door handles with a different lock from like a toyota or any car, as well as the ignition keyhole and still have the car be opened and turned on.

 

Anything is possible with the right amount of effort. In general, none of those parts are interchangeable with other manufacturers.

 

With the right amount off effort requires the right amount of money $$$