Hello its good to hear from a fellow ravian....

First of all there are no special requirements for becoming an ASP except those mentioned in the outline given by the fpsc they pertain to eye sight and height.one more that now days in order to become an ASP one needs to secure very good position .Regarding subjects its totally up to you.choose the subjects you are familiar with and can grasp them easily as one score's only in those subjects over which one has good grip.I know people who have become ASP'S with arts subjects like history,political science etc and others with science subjects like physics,chemistry etc.
if you are cpompleting your degree at gcu,why would you want to get a private B.A degree from PU.i think its of no use but if you have some troulble at gcu then obviously B.A from P.U is the only way out.
take care