Since Laurie answered most of the question, I'll answer the rest.
The link she posted to the 2nd thread (my article) has pictures of some of the WDW Companion Restrooms. They are not all the same and, depending on needs of the person, some may work better than others. I do have pictures and measurements of all of them, just have not had time to post anything other than Epcot pictures and measurements. I'll try to get at least the measurements and locations for the other parks this weekend. As you might guess, the pictures are rather time consuming to put together.
If you have specific questions about any park or DTD, let me know.
The locations are not listed in the regular park maps, but there is an icon for them on the new Guidemaps for Guests with Disabilities (which replace the older Guidebooks for each park). When you go to Guest Relations at any park, the new guidemap is what you will get. You can still access the Guidebooks on the Disney website (there are links to them in post #3 of the disABILITIES FAQs thread). The general one has information about Companion Restrooms. When Disney updated their website recently, they had some problems with formatting, so some things are not lined up correctly (at least when I view them).