This game will have separate routes for main girls. But harem path will be the main path.
Eva and Maat are side girls but Carib said we might see them in the future updates.
Well i don't know about future of this but in old one we only had things with main girls or all girls just become main,as far as I know there was just 4 main girls till half of the game and other 3 just become main somehow,and specifically for these 4 we had rival(weak )but antagonist was there to steal them away,i doubt someone had let them do that ,and for others it was just our choice,so i think side girls will join harem in the end but not sure