USC Decision Date?

Do decisions come out earlier for those who applied by the scholarship deadline? Or are all decisions released by April 1st?

No. If you applied by December 1st and end up getting offered some form of merit scholarship, you will in fact also know that you were admitted. But that is limited to around 800-1,000 successful applicants of the many thousands who applied early. That group finds out in late January to early February.

For all others who applied early, the decision is rolled-over. They will find out with everyone else in late March or at least by April 1st. 55K+ applicants then most likely will not hear until everyone hears together. Only the initial 800-1000 or so who hear in January know for sure before March. And no one is rejected in Jan-Feb.