What if Davepetasprite^2's purpose is to interact and possibly remove the ARquissprite part of Lord English?

That would just create a doomed Arquiusprite assuming the pre-retcon one came over with all the other sprites. And even if that’s not the case what you’re describing would be an ability of a Rogue of Heart which is Nepeta’s class but typically when two people merge so does their classpect (such as Erisol acting as a Prince of Doom, destroying his own doom ie not being able to spritesplode even though he was miserable). If anything, I feel Davepeta will act more as a Knight of Heart. Knights exploiting and protecting their aspect and Heart being an aspect of the self, the soul, the personality and motivation. That’s just my opinion however.