Ok so I found some sounds I can use, kind of like the ones you had there...They'll do in the interim until you get them backed in. I added the accepted sound as you stated...I'll do some testing and see if it works ok or not.
EDITED: After adding the unrecognized sound to F_AVCS_VAS_INVALID_COMMAND I found that it was playing this sound for all kinds of stuff that it couldn't recognize. From hearing the dog barking to my own breathing. I guess I didn't notice that VA was picking all that stuff up until I heard it playing the unrecognized sound all the time. So I removed it since it isn't too helpful anyway. Knowing that I should hear the "beep beep" sound after a correctly recognized command was enough for me. if I don't here the beep beep sound I added then I know it didn't get what I said and I repeat it. Works pretty well. Maybe you can come up with something fancier than that. My next test will be enabling all humans flight with PTT set to OFF and see if that works well. if so I will most likely keep it that way, typically I only fly with people and not a mix of AI other than normal ones AWACS, TOWER, TANKER.