Hi Oleg,
In fact, there's not much depth information about APO on HANA out there (focusing on specific components' functionalities).
Nevertheless, I've found a few pages that might help the comprehension of the SCM-HANA link and the components included on HANA.
Please, refer to them:
"How-to" guide which details the technical impacts of the migration SCM-HANA
Article about Demand Planning and SNP
I hope it helps you, Oleg.
Thank you,
Pablo Moraes