I thought the elevator feed also fed the controls. Can a vfd output be used for controls? At least a rotary phase converter has two legs with a steady voltage, but the connection would be important.
Check with the elevator people. I had a project with a number of Kone elevators, and they would not except anyting but a utility supplied three phase system.
My next door neighbor (Shop) is an elevator co. Mostly home and small commercial units. Many come with 3 ph motors set up to work with 240v 1ph with a VFD.
Interesting to note how setups vary - in Europe older elevators typically used 3ph motors with separate windings for softer braking (still not extremely comfortable of course).