re: The steam thing. As far as I can make sense of this, its just preventing devs from signing a steamworks contract to release a game THEN staying off steam whilst on epic etc. Nothing prevents you releasing on epic for a year, THEN going to steam for release later.
well to be fair phpBB IS a pain in the ass, even if the more recent version got better. But one can always use http://itch.io forums for free anyway if they want :)