You have nothing on several Pokemon.
odeergodwhatareyoudoing
Okay, Give Reuniclus a Life Orb. Magic Guard negates the damage.
Serperior I would give left overs.
Correct choice on Wacan berry on Mantine.
Choice Band on Scrafty.
Possibly Choice Specs on Chandelure, although a Colbur berry is definitely something to consider.
Berries on the rest I'll leave up to you.
Give that Flygon U-Turn and a Choice Scarf.Earthquake is good. You might want to Replace Dragon Claw with Outrage, but first, test it out someplace like PWT to make sure you like it. I think Outrage would go much better, though.
As for Serperior, I don't think that moveset is a good idea. Have you tried running a subseed set?
So Rest is a non-option. Rest works great with Shed Skin, but not so much with Moxie...
Drain Punch would have been a good option, but that's an egg move. I'd replace Brick Break with Hi Jump Kick, but that' just me.