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This should be a lot of fun, and a great way to separate Ubers from the lower tiers. While OHKO clause probably isn't a big deal, Species, Sleep, and Evasion most certainly will. A lot more people are going to start running Sleep Talkers to combat this. Heck, running 2 Kyogre would be a lot of...
Using 2 RestTalkers would be inadvisable. Instead, make the following changes:
Focus Sash on Darkrai. Not only does this give you a chance to take an Extremespeed and fire off a Dark Void, but it also allows him to function as an anti-lead if necessary.
Switch Scarf Zekrom with Scarf Palkia...