Guests usually rush to Indy. Pirates and HM are usually walk ons for about a half hour or so, at least from my experience. The HM will be busier because of the overlay, but not super busy that early. As another poster said, HM has FP now so you can always get that first and hit Pirates after.
We went in August, and immediately got a FP for Indy. We went to Pirates next and literally walked on to a boat. Then we went to HM and there was maybe 20 people ahead of us. But that was just our experience, every day of the year is probably different!