Since there are no minimum stay requirements, you're a-ok. Also, it often makes sense to "break the fare" at a certain location like ATL as you've done since it's cheaper. When you book "back-to-back" to avoid for example a Sat. night stay that you might get into trouble. In your case, if you misconnect on any of your flights, you'll probably be on standby for the rest of your itinerary but probably won't be left high and dry.