No the ergos are not the same between the different Shadows. Even the older VT1100C has different ergos than the newer Spirit 1100, ACE 1100, Sabre 1100, etc.
The VLX makes a great beginner bike. They weigh less than 500 pounds, they have decent power up to 70mph (mine topped out over 85mph), simple to maintain, parts are cheap, easy to handle, sit low to the ground, etc. You can easily find used ones under $2k if you look at mid- to late-90's models (nothing major changed on them during the years, except for a minor cosmetic make over in 1999).
Aero's have a lower seat height than the Spirits. Find a 1100 Aero and let her check it out, if she rode the Spirit the Aero will fit her a lot better and not be as heavy feeling. I had a Aero 750 it was nice and low, I am over 6'...did not need low, but for those that do they are great! Good luck, post pics when you get it!
With the exception of the VT500C, all Shadows have forward controls, a possible issue with riders with shorter inseams. The VLX is a possible option and an excellent suggestion. The VT500C, made from '83-'86, is also a possibility if you can find one but it is an older style. The VT500C is a mid controls bike, 50hp, under 400lb, and would be an easy step up from a rebel.