ED should not affect application process, just be aware you might get pulled aside on first entry for them to check some thing on the system, should be relatively painless (happened to me). If applying before ED runs out make sure actually you cancel it before you leave, don't just depend on exit =cancellation scenario, school should be able to advise on that. As to the 500k, not all embassys require it to be there for 6 months, check posts here for which don't