You should not be able to use both REAP and the new Post 9/11 GI Bill at the same time; you cannot be enrolled in two forms of VA-provided educational assistance at the same time. Tuition Assistance (TA) is provided by individual services, and so it can be combined with VA educational benefits, but the rules are different for that. When you use the GI Bill along with Tuition Assistance, the GI Bill only pays the portion of your tuition over what TA pays for.
In order to make sure that you continue to receive full benefits from the GI Bill, you should make sure that, regardless of the dates at which classes begin and end at your colleges, you are always taking a full load. Short breaks between terms can be okay, but if you can’t verify that you are taking a full load once a month, your GI Bill benefits will be decreased.
The housing stipend rate for the new GI Bill is based on the location of the school where you take your actual classroom courses. Online courses don’t make you eligible for the housing stipend at all; if you aren’t taking any classroom courses, but only online courses, you don’t get a housing stipend.