Yes and yes! We just did 2 days with a park hopper and max pass. It just makes it so much easier. We didn't have to figure out where the fast pass distributions were...so easy to use our phones!
On our first day we went to DL. My youngest daughter didn't want to hop to DCA because she wanted to keep it special for the next day. We had never been before! On the 2nd day, we started at DCA, and hopped over to DL in the afternoon to ride our favorite rides from the day before and then we kept watch on our phone so we could get a fast pass for RSR and the Incredicoaster for night...so when it got dark we hopped back to DCA rode those rides and watched World of Color!
I hope this helps! Happy Planning!