Crack idea, but Parent trap & pho crossover. Where two identical twins are put up for adoption by a mortal who go busy with a god, and they are both raised by single parents who independently adopted them, and the twins, Halle and Annie, manage to survive long enough to get to camp half blood. They eventually get claimed by Dionysus, and his kids are graduated (or dead…) and now have to share a cabin alone, realizing the situation, they switch places once the summer is over to try and set their very single parents up together. Yes Meredith Blake would 100% be a monster disguised by the mist.