This is the simplest and most accurate way to describe few technical titles and their real meaning:
Advisor - A fake designation. It is not even an official title but highly abused. E.g. when a worthless employee from one organization transfers to another one and no one knows what to do with the useless person, they name him/her an Advisor.
STP-A Senior Advisors are people who do not want to do any work and are only interested in showing off and networking
STP-C Senior Technical Consultants – mixed bag of failed low level management or few technical folks who have no interest in producing any kind of focused in-depth technical work
Chief Scientists/Engineers: Utterly failed second level managers