From my discussions with college counselors the biggest problem with virtual students is lack of interactive classroom experience. As one counselor said to me, you can be the smartest person in the world but if your classes are all online, then we don’t know if you can handle a class room environment.
For the above reason, I would take as many DE classes as your school and CC allow in the first semester of your final year. The reason for this is so that schools can see you first semester grades before they make acceptance decisions.
I would take the science course as a first choice for DE. This is for two reasons, first it shows that you have experience with group work (labs) and it shows that you have actually taken wet labs. Many online providers don’t offer a wet lab option. Not sure about yours, but I know here in CA, the UCs don’t accept some of the virtual science courses for that reason.
I would not waste precious time with the ACT or Lit retake. You will soon find out that the actual college application procedure will take up much of your time, and that time is limited. There simply are not enough hours in the day to do it all.