I bought physical copies of some of the books through my LGS, so Demiplane expects me to buy the digital copies from them to be able to use the ancestries?
Our Pathfinder 2e digital sourcebooks and toolset are a separate product and purchase from other versions of the books. Much like the Core Rulebook and the Core Rulebook Pocket Edition are different products.
However our Paizo Connect function does allow us to provide a deep discount on any books for which you already own the PDF. You should see this discount appear once you have linked your Paizo account.
I bought the books through my LGS, so there was no Pazio purchase.