They did refer to them as "The Third Force" so imo this means that Sasuke's group will be their own side with no alliance. However Naruto would manage to persuade Sasuke to help him defeat Madara, probably promising him a fight or something :crazy:
Ψ Can you hear it? The screams of all the meek in the world... Shall create a scorge of fear and despair to all. To those who band together and create an insurrection, shall be punished, for their inequity. Narutobase, your time...will come! Ψ
Re: What will happen if sasuke joins the fight ?
I do want to see Sasuke meet Madara tho. It will be pretty interesting how that turns out.
There really is no benefit for him to join either side if he fights along side The Allied SF it's "Thanks for the assist you're under arrest" If he helps Madara and Obito it's "Thanks for the assist you're under a spell" it's a "Catch 22"