Mixed Jirachi is better off as a SmashPass recipient, IMO. But if you want to keep it mixed, that's fine, but it needs better coverage options:
-Iron Head
-Fire Punch
-Hidden Power (Ice)
-Energy Ball
Nature: Hasty
EVs: 152 Atk/204 SAtk/152 Spe
Item: Expert Belt
or
-Substitute
-Calm Mind
-Thunderbolt
-Flash Cannon/Psyshock/Water Pulse
Nature: Timid
EVs: 252 HP/104 SAtk/152 Spe
Item: Leftovers
or
-Iron Head
-Body Slam/Thunder Wave
-Wish
-Stealth Rock/Protect/U-turn
Nature: Careful
EVs: 252 HP/236 SDef/20 Spe
Item: Leftovers
or
-Iron Head
-Ice Punch
-Fire Punch/Healing Wish
-U-turn/Trick
Nature: Jolly/Adamant
EVs: 252 SAtk/4 SDef/252 Spe
Item: Choice Scarf
or
-Wish
-Calm Mind
-Thunderbolt
-Flash Cannon/Psyshock/Water Pulse
Nature: Bold
EVs: 252 HP/236 Def/20 Spe
Item: Leftovers
or
-Substitute
-Body Slam/Thunder Wave
-Iron Head
-Fire Punch/Zen Headbutt
Nature: Jolly
EVs: 252 HP/160 Atk/96 Spe
Item: Leftovers
Jolly lowers Infernape's Special Attack making Flamethrower less useful. Gems aren't useful except for Flying Gem + Acrobatics, IMO:
-Flare Blitz
-Close Combat
-U-turn
-Mach Punch/ThunderPunch
Nature: Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Choice Band
or
-Fire Blast
-Close Combat
-Grass Knot/U-turn/ThunderPunch
-Stone Edge/Mach Punch/ThunderPunch
Nature: Hasty/Naive
EVs: 252 Atk/4 SAtk/252 Spe
Item: Life Orb
or
-Fire Blast
-Close Combat
-U-turn
-Hidden Power (Ice)/Stone Edge
Nature: Hasty/Naive
EVs: 108 Atk/148 SAtk/252 Spe
Item: Life Orb
While Foul Play's 95 base power seems tempting, don't bother with it because it uses the opponent's Attack rather than Zoroark's to calculate damage (it's better on Pokémon that lack offensive presence, like Sableye or Umbreon, IMO). Also, its Special Attack is rather good, so why aren't you using Dark Pulse/Night Daze?:
-Dark Pulse/Night Daze
-Flamethrower
-Focus Blast
-Sucker Punch
Nature: Naive
EVs: 4 Atk/252 SAtk/224 Spe
Item: Life Orb
or
-Dark Pulse/Night Daze
-Flamethrower
-Focus Blast
-Nasty Plot/Trick/U-turn
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Life Orb/Focus Sash (former 2 for Nasty Plot)/Choice Specs/Choice Scarf (latter 2 for Trick/U-turn)
Haxorus gained more coverage options in B2/W2 in the forms of Superpower, Low Kick and Aqua Tail. Also, Lum >>>> Persim, as Lum cures any status Haxorus takes and confusion isn't the only status that can screw it over:
-Swords Dance
-Outrage
-Superpower/Low Kick
-Substitute/Aqua Tail/Earthquake
Nature: Adamant
EVs: 4 HP/252 Atk/252 Spe
Item: Fighting Gem/Lum Berry/Life Orb
Ability: Mold Breaker
or
-Outrage
-Superpower
-Earthquake
-Aqua Tail/Dual Chop
Nature: Adamant/Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Choice Band
Ability: Mold Breaker
or
-Dragon Dance
-Swords Dance
-Outrage
-Low Kick/Earthquake
Nature: Adamant/Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Lum Berry/Draco Plate
or
-Dragon Dance
-Outrage
-Low Kick
-Earthquake/Taunt/Dragon Claw/Dual Chop
Nature: Adamant/Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Lum Berry/Yache Berry
Ability: Mold Breaker
I feel that Rotom could be a bit faster. Also, Shadow Ball is rather useless on it as a neutral STAB Hydro Pump does more than an unSTABed supereffective Shadow Ball:
-Volt Switch
-Hydro Pump
-Will-o-Wisp
-Pain Split/Hidden Power (Ice)
Nature: Modest
EVs: 232 HP/68 SAtk/208 Spe
Item: Leftovers
or
-Volt Switch
-Hydro Pump
-Thunder Wave/Will-o-Wisp
-Pain Split
Nature: Calm
EVs: 248 HP/28 SAtk/232 SDef
Item: Leftovers
or
-Volt Switch
-Hydro Pump
-Hidden Power (Ice)
-Trick/Thunderbolt
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Choice Specs/Choice Scarf
I think Jellicent should be Choiced if it runs an offensive set as it lacks power somewhat:
-Water Spout
-Hydro Pump/Surf/Scald
-Shadow Ball
-Ice Beam/Giga Drain
Nature: Modest
EVs: 172 HP/252 SAtk/84 Spe
Item: Choice Specs
Ability: Water Absorb
Or it can go defensive, since Jellicent is primarily a defensive 'mon:
-Scald/Surf
-Will-o-Wisp
-Recover
-Taunt
Nature: Bold
EVs: 248 HP/216 Def/44 Spe
Item: Leftovers
or
-Scald/Surf
-Will-o-Wisp
-Recover
-Shadow Ball/Ice Beam
Nature: Calm
EVs: 252 HP/36 Def/220 SDef
Item: Leftovers
Ability: Water Absorb