I’d like to do fun things with Android Nearby Connections 2.0, but I wasn’t clear from the announcement which of the technologies (messaging, file transfer, socket-like comms, etc) can have a non-android endpoint. For example, if I want my android phone to control my LeJOS (java) legos, can I? Or do all endpoints (even the whiteboards, RC cars, etc) need all endpoints to be Android (or Android Things) OS?
From the announcement post link you gave:
Today we’re announcing the availability of this API across
all Android devices running Google Play services 11.0 and up.
I think that answers your question. Should Google provide a implementation for devices not running Android and not running Google Play then non-Android endpoints would be possible.