EVA is completely separate of the digital dash's, you could, if you wanted, have EVA in a car with an analog dash but they were not sold that way
However I do think on the left hand side of the k-body dashes can either be an electronic tach or a system check (picture of the car, with lights of problem areas). The voice system does piggy-bag electrically off this. It is the 11-function system.
Similar to the G/J body, but systems check is in the center below the navigator, this is the 24 function system
Adding EVA no matter what is an installation from scratch, the 11 function system would be less wires than the 24 function. I put the 24 function system in my 89 Daytona Shelby out of an 86 Laser XT, complete except for the brake pad and oil dipstick sensor and it took many late nights, tore entire dash apart and most of the car to run wiring for sensors.
You will need all of the plugs, the EVA ones are very unique like a SNES cartridge. If you want most of the sensor functions to work you will need to rob the sensors off the donor car, some are still available new from rockauto as well. A factory service manual for your car and the doner car is pretty much a must as well.
This is a link to a very helpful site, but it doesn't have all the info you need to complete the job
The Chrysler Electronic Voice Alert