as representing yourself in a short sale, we just purchased a short sale with two liens. The only complicated part can be that you will likely need to be able to close very quickly when the approval comes through. In our case, the second came through in and said, you have to close in about 12 days. Luckily, we had everything set and could do it.
Just know that they will likely make you raise the price a bit to approve the sale. Generally about 5k. Just because they can. It's a pure cash grab. Also, if there is a second, they might be difficult just because they are getting nothing. But generally once you submit it for approval, it should be pretty smooth sailing as long as you agree to the random terms the bank throws your way.