1. You can apply anywhere you want (with no guarantee of success).
2. Typically you can do any rotation you want. Each school has different 4th year requirements, however. Only COMP would have specific information for you.
From what I know it is largely dependent on the hospital. I have heard there are places that won't let DO students rotate but don't know of any. Go to the residency web pages, it usually explains the process for Sub-I's. Look at the links below, you can find tons of info on the programs websites.