You don't have much of a chance, seeing how Shedinja and Skeptile will be taken out when they face a steel type, and Menetric will be taken out with Metagross' first Earthquake. I'd say that you Rare Candy each of your 3 fainted pokes, thereby reviving them, then healing. Just my opinion, wait for others if you feel like it.
By the way: Drop Thunder on Manetric and Cut on Shedinja as soon as possible... never double the type on one poke, and Cut is useless.