I also currently participate in what is called the Innovation Advancement clinic at ASU law. We do consulting and legal work for individuals and startups that cannot afford conventional legal services and consulting. I think this will help my chances at ASU, since I am already working with a clinic at the school and would transition straight into that program once I am admitted. I think I can also get a good LOR from the chair of the program who works for the school and has to work with us hand in hand. This is something else I wanted to touch on in my PS.
They'll be decent soft factors, but not game-changers. They will help you immensely during the interview/job hunt however.
Your PS on the volunteer work sounds great. Don't make it worse by talking about your work at the IA Clinic. You have 2 double-spaced pages to tell a story that defines you as a person. If you try to tell more than one story, you won't tell either well. Pick one or the other (I'd go with the volunteer work, as you can get the Clinic work into your package through a LoR) and stick to it. The PS is a laser beam, not a shot gun.