[X] Grind Them Down - Keeping Blissey in so that she can wear down Starmie does risk a freeze or paralysis causing problems down the line. But she can use Soft-Boiled now to get to full health then interspersed repeated Protects, Soft-Boiled, and Life Dew to stall further. You will have to include the occasional rest, however, to keep Blissey fighting. Eventually, Willow will have to switch back to Minun where the buffs will be reset and you can send out Umbreon to defeat them.