The Rehabilitation Act of 1973 is related to a vocational program for a job. You bought up the IDEA. I believe that you are correct.
The ADA is different from the IDEA. The ADA requires managers and bosses to accept to meet people's needs such better equipment like a new chair, better light environment room, transportations, etc. The ADA is most related to handicapped employees. The problem is that many people still talk about that ADA for school programs. It should be discussed in IDEA instead.
Interpreter providers(?) for hearing impaired are involved in both ADA and Rehabilitation Act of 1973 - i.e. a company pays some interpreters for job interviewers, important lectures (i.e. OSHA laws), and police arrest deaf people that demand for interpreter(s).
I didn't want to detail it because it is complicated for me to understand the laws. (Isn't this info correct? A deaf man lectured in a class about ADA issues a long time ago, and I recalled about it.)