It is also worth noting that even though a commuter clause is in effect, it is best policy for pilots on probation to not miss their commutes. You just don't want to talk to anyone in scheduling (i.e. management) any more than you have to. Yes, we have protection, but it's also better not to need to use it very often during your first year on the line.
As for junior and senior bases, that seems be in flux. ORF is growing and DCA is shrinking. As to where you might go as a new hire? ORF is a pretty good guess. But as long as AWAC keeps hiring there are frequent vacancies and people can change around pretty easily.
A new pilot could probably get PHL pretty easily but would also probably be on RSV longer. Most people go for getting a line earlier rather than later even if it means going to a less desirable domicile.