I followed one of her plans and it ended up in Himari going stupid, was that me failing the plan or was it as scripted?The true ending is fairly complicated. You need to get all 3 other contestants on your side. Find Himari's stamp, correctly solve the chemical puzzle for Abigail, help Katelyn get over her cleaning compulsion.
After a while Ashley will start coming up with plans to beat Erica. If you follow and execute the plan properly and beat Erica, you'll move onto the true ending. Though it's still in heavy WIP at the moment.