Yes, it’s possible to do CS in CoE and econ in LSA. I highly recommend that you just do them both in LSA, though. Dealing with 2 colleges presents logistical issues, and there is virtually no upside to doing CS in CoE. It would be a wise investment to simply convince your parents to let you do the double major now, instead of having to deal with administrative issues with the colleges down the road. It may help your case if you inform your parents that the dual degree would require you to pay CoE’s tuition (more expensive) compared to LSA tuition.