PPM plugin for MS Project is currently not certified with MS Project 2016 (might work, might not work, but it won't be officially supported), and definitely doesn't work with Project Online as it's a completely different technology.
You will never get an official answer from HPE when asking a question about future features or support that aren't in the product yet. All I can say is:
- We're currently working on it. (That's it for the good news part :) )
- Support for Project Online will require to completely reconsider how PPM integrates with MS Project, as the current PPM Plugin for MS Project is based on .Net Add-In technology, which does NOT work with Project Online nor any product from the Office 365 suite.
- If something gets delivered to support Project Online (and MS Project 2016), that very likely won't happen before the end of Fiscal Year 2016 (i.e. late Autumn 2016). Might be later. Might be never. No official date nor commitment, sorry!