I'm somewhat familiar with these schools. I visited almost all of them, have worked with attorneys from most (if not all), and have friends who went to others.
It sounds like you're pretty set on Chapman, and with an 80% scholarship that's understandable. Chapman has the nicest campus of any of the SoCal schools you're looking at. I was really impressed with their law school building. That's not a huge factor, but if you have to spend three years somewhere you want it to be pleasant.
The main factor I think you need to consider (after expense) is location. Chapman will give you better opportunities in Orange County, but Southwestern, Loyola, and Pepperdine are far better established in LA. There are lots of Chapman grads working in OC as prosecutors, county counsel, etc., but not as many in LA. That doesn't mean that each school will absolutely limit you to it's immediate area, but it will be tougher to compete for jobs in LA if you're competing against LA area students who have been able to make connections.
Between Chapman and Southwestern, I'd be inclined to take the option with the least debt. There is really no reputational advantage between the two, in my opinion. I think most employers will view them as basically on the same level. The only reason to consider SW at a higher cost is if you are determined to work in LA.
As far as the San Diego schools, I'd only consider them if I was willing to live in SD. It will be difficult to make connections in the LA area and to obtain internships if you're in SD. USD has a decent local reputation, but it's not so strong that it's going to open many doors outside of SD. The LA area is already so flooded with local grads that it won't make much difference.
If you get into Loyola or Pepperdine it may very well be at sticker price. Personally, I don't think either of those schools at full price is a better option than Chapman or SW at a substantial discount. Again, they're each good schools but they're not elite
. They are ranked higher, true, but take those rankings with a grain of salt. Nobody is going to be so blown away by a Pepperdine degree that they'll offer you a job based on pedigree alone. To get hired at the DA you're still going to have to make connections.
That's not to say that it doesn't matter at all. Loyola, especially, is held in good regard and a degree from Loyola combined with relevant experience might have an advantage over a degree from Chapman or SW with the same experience. But just keep it in perspective.
If you were trying to decide between UCLA and Chapman/SW, UCLA might win. But as between schools like Chapman, Southwestern, Loyola, etc., the decision becomes murkier.
I currently aspire to be a DA, in the SoCal/LA County/Orange area. I want to go to a school for their criminal litigation/trial advocacy programs, clinics, academia, and alumni network. Quality of life inherent from their campus and location is of consideration to me.
A word about getting hired as a DA. The DA's office is probably the most competitive government law office in terms of hiring. LOTS
of people want to be DAs, and hiring in most counties is currently very low. When a position opens it is not unusual to get literally hundreds of applicants. People who have crimlaw experience and personal connections (such as having worked at that office as an intern) will have a distinct advantage. Obviously, grades and class rank will matter too, but connections and experience are really the key.
The reason I'm pointing out the highly competitive nature of DA hiring is because you should go into law school with a flexible attitude. The fact is, the vast majority of aspiring DAs will not become prosecutors. Trust me, half the people in your class plan on being DAs. It's good to understand early on that you may end up doing employment law, family law, or defending DUIs. In this market you need to be willing to go where the jobs are.
Hope that helped, Good Luck with your decision!