How has Banette done against Aerodactyl leads, you're never going to outspeed them so they can simply Taunt. I look at you running Jolly 252 but it still doesnt quite get there. I was going to suggest
Trick Scarf Uxie to deal with this Speed problem, but I'll let you make that descision, as you do lose the Will-o-Wisp, and you no longer "beat" Psychic types. So keep Banette as it is but if you have Aerodactly problems, try out Uxie. Also you only get one extra stat point for every four EVs, so I'd change Banettes EV spread to 252 HP / 196 Atk / 60 Def this ensures an OHKO on Gengar after Stealth Rock and will OHKO without 25% of the time, something that a pokemon like this banette should really be doing :P
Hidden Power Ice isn't what you should really be having on Magnezone, if you have the Ice coverage elsewhere, don't you know that HP Grass is all the rage these days, you easily beat Swampert with a swift Magnet Rise and then Hidden Power Grass, although if you want to actually do some damage to Scizor before dying go with a more offensive Magnezone, I ran:
Magnezone @ Life Orb
Timid Nature / Magnet Pull
EVs: 252 SpA / 252 Spe / 4 HP
~ Thunderbolt
~ Hidden Power Grass
~ Magnet Rise
~ Explosion
I found the two most common switchins after succesfully killing a Skarmory or a Forretress were either a Swampert or a Blissey, against Swampert I used Magnet Rise and then HP Grass against Blissey I exploded, many didn't suspect it, but offensive Zone is the way to go at the moment because:
Thunderbolt vs. Standard Scizor: 84-100%
Your Magnezone vs Standard Scizor: 65-77%
A very minor thing also you have 4 remaining EVs left on Forretress, why not chuck those into Attack, and give it Shed Shell, it is just as important that forretress has shed shell as it is that Skarmory does.
As for problems that you team might have, Swampert originally came to mind but we've dealt with that with Magnezone but "Bulky Waters" still reamin, Magnezone doesn't really want to be constantly switching in, I guess you could chuck Toxic on Suicune as they wall that quite nicely, it could perhaps go over Rest or possibly Ice Beam I don't know try it out and see what happens, but apart from that it looks all good. I hope some of this helpes =D