Unless they changed it over the years, I have always used [Flash]#1 to activate camp-on on Analog phones, and if you later need to cancel that you can pick up the phone and dial ##1. If the phone doesn't have a flash key on it you han use a 2 second press of the hookswitch to do it. I always press it while saying "Down -- Up" at a reasonable speed.
If that doesn't work you should be able to use DIS-WABE:GEN; to display everything in the dial plan and the code should be listed in there.
I can't speak on changing the tones. Most of the feature activation codes are signalled with a stutter dial tone. I know I had to train the nurses for the patient room phones that if the phone has a stutter dial tone they should dial ##5 (deactivate DND) and ##91 (deactivate forwarding) - that usually takes care of it.....