Is there a way to add previous year's report cards to the Report Card History?
There's no built-in method to add previous year's report cards, however in theory this could be done by generating the report card history in prior-years and then copying those records to the current year in the backend (SQL). Aeries Support could probably assist with this, or provide additional insight if you'd like to contact them.
I have already initiated a ticket. Support is working on it.