Alright, let's see what you can do here
For Marshal you have Espeon, so he's covered, but if he has Scrafty, keep Flygon alive at all costs and spam Fly on it.
For Caitlin you have Shadow Ball and Bite on Espeon, Signal Beam on Amphy, Crunch on Arcanine, and Megahorn on Samurott. Watch out for Sigilyph's Thunderbolt, Gothitelle's Thunderbolt, and Reuniclus' Thunder. A lot of Caitlin's Pokemon have Shadow Ball, so watch out for that.
For Grimsley just spam Close Combat and Aura Sphere with Lucario, and Megahorn with Samurott. GG
Shauntal may be tough. Her Cofagrigus can take a Shadow Ball really well, and Chandy could destroy your team if you're not careful. Save Amphy for the Jellicent
Iris can be a pain in the ass. Put Samurott in front so it can kill Hydreigon with Ice Beam or Megahorn. Lapras and Aggron die to Lucario's Aura Sphere and Close Combat. Archeops becomes powerless because of Defeatist, so get it down to half health as soon as possible. Druddigon can be a pain. Spam Ice Beam on it with Samurott but watch out for Thunderpunch. You always have Ice Punch on Lucario so that helps. If you have Intimidate on Arcanine, that takes care of Haxorus, but if you don't, switch in Amphy when it uses Dragon Claw so it takes Rocky Helmet damage.
Hope I helped!