That explanation just shoehorns additional headcanon into the equation where none is actually needed, especially since party or no, a Necrolord Maw Walker cannot and will not experience what a Venthyr Maw Walker would, and vice-versa. Yet all these events still occur, because (as has been stated half a dozen times now) the developers are on record that there are multiple Maw Walkers. There's no need need to bend canon into a pretzel when a developer statement quickly and easily resolves the issue presented. There are no flaws with the notion that there are multiple Maw Walkers and it allows all the Covenant storylines to occur naturally and dovetail seamlessly, just as they do in the in-game experience.