Neither original post nor the second question by Mirtexxan seems to be answered so I would like to give this post a bump.
Can twilight speaker use and grant rage powers?
Does community domain grant spells known or spell slots prepared?
Given that designer intent is clearly for them to provide Rage Powers, and especially since they still acquire Rage Powers at the normal levels, it's hard to justify locking them out of granting their Powers.
Given that I'm not aware of any Spontaneous casters who have prepared domain slots or any similar setup, they should probably get the Community bonuses as additional spells known.