Help improve my OU team?

[εcho.]

Been playing on Showdown in OU singles with this team and am really enjoying it.
Any suggestions on how I can improve it?

Saf (Greninja) @ Focus Sash
Protean | Timid
252 SpA / 252 Spe / 4 Def
Spikes
Dark Pulse
Surf
Ice Beam

My lead for the team, to either set up spikes or take down opponent's lead if possible. Focus sash allows him to endure a hit and retaliate against anything faster than him.

Bitterblue (Togekiss) @ Leftovers
Serene Grace | Calm
248 HP / 252 SpD / 8 Spe
Air Slash
Thunder Wave
Dazzling Gleam
Roost

The classic Paraflinch Togekiss. Been thinking of switching her over to more of an offensive Nasty Plot set but not sure about that atm.

Brigan (Excadrill) @ Air Balloon
Mold Breaker | Adamant
176 HP / 52 Atk / 80 Def / 202 SpD
Rapid Spin
Earthquake
Swords Dance
Rock Slide

Rapid-spinner to get rid of hazards, set-up if possible to take down a few mons. Air balloon allows him to switch in safely on ground type moves.

Fire (Talonflame) @ Sharp Beak
Gale Wings | Adamant
252 Atk / 252 Spe / 4 HP
Brave Bird
U-Turn
Flare Blitz
Swords Dance

Swords dance Talonflame. If I can time it right with predicting opponents moves, once she's set up with a Swords Dance she can do some brutal damage before finally fainting.

Po (Dragonite) @ Weakness Policy
Multiscale | Adamant
252 Atk / 252 Spe / 4 HP
Dragon Dance
Fire Punch
Extremespeed
Dragon Claw

If I can get him set up, this guy can just obliterate an entire team. Multiscale allows him to take supereffective hits from full health to activate the Weakness Policy. Combined with a Dragon Dance to boost Speed, he makes a fantastic physical sweeper.

Katsa (Espeon) @ Leftovers
Magic Bounce | Timid
252 SpA / 252 Spe / 4 HP
Calm Mind
Dazzling Gleam
Psyshock
Shadow Ball

False lead and my switch in for when I predict status moves. Special sweeper if I can get find a chance for her to set up.

 

[PlatinumDude]

Talonflame needs Roost so that it can heal off the recoil damage it takes from its STABs. Assuming a 31 HP IV, putting 4 EVs into Talonflame's HP makes it even, meaning it takes 2 Stealth Rock switch-ins at full health to KO it. Either one of these sets should be used:
-Flare Blitz
-Brave Bird
-U-turn
-Tailwind/Roost
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Choice Band/Sharp Beak/Sky Plate
Ability: Gale Wings

or
-Swords Dance
-Flare Blitz
-Brave Bird
-Roost
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Life Orb/Sharp Beak/Sky Plate
Ability: Gale Wings

I think Excadrill could use some extra Speed: 252 Atk/4 Def/252 Spe. What KOs does Excadrill avoid with its current spread?

Offensive Espeon isn't viable. It's outclassed by other offensive Psychic Pokemon such as Lati@s and Speed Deoxys, which pack better coverage moves than Espeon does. It's also horridly frail and has difficulty setting up Calm Mind. Sure, Magic Bounce repels status moves, but you have to worry about strong offensive moves as well. It's also very prone to priority. This is the best Espeon can do, I'm afraid:
-Reflect
-Light Screen
-Psychic/Psyshock/Yawn
-Baton Pass
Nature: Timid
EVs: 252 HP/4 Def/252 Spe
Item: Light Clay
Ability: Magic Bounce

 

[εcho.]

What would be a good Latias set to replace Espeon?

 

[PlatinumDude]

What would be a good Latias set to replace Espeon?

Latias:
-Draco Meteor
-Psyshock/Thunderbolt
-Defog
-Roost/Recover/Healing Wish
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb

 

[εcho.]

Thanks, I'll give that a shot and see how it goes.

Edit: I missed your Excadrill question in your first post. The answer is, I don't really know. It's a spread I found somewhere and was just trying it out. I'll try what you suggested and see if it works better. Also thinking about switching his balloon to a focus sash as well.