Can you enter your freshman athletes so that their Middle School PR's show up?
Yes. Typically related high schools and middle schools are linked, so that MS students can be transferred between the schools. I've linked your HS with the MS. You can now use the Advanced Athlete Editor on the Edit Athletes page to move students to the HS.
In addition, we can link any athletes together. For example, if an athlete switches schools, we can link the profiles together.
So, probably your best option is use the Advanced Athlete Editor to move athletes to the HS. It will create duplicate athletes today if you have already added them HS side, but they will be merged by tonight, linking their accounts.