Help? My semi competitive team

This is my battle team:

Alakazam
Lvl 69
Iv 31/x/31/31/31/31
Nature: Modest
Ability: Magic Guard
Item: Mind Plate
Move set:
Psychic
Dazzling Gleam
Calm Mind
Shadow Ball

Arcanine (Alec)
Lvl 61
Iv x/31/31/x/31/31
Nature: Adamant
Ability: Intimidate
Item: King's Rock
Move set:
Extreme Speed
Crunch
Flare Blitz
Close Combat

Mismagius (Giggles)
Lvl 77
Iv 31/x/31/31/31/31
Nature: Timid
Ability: Levitate
Item: None
Move set:
Magical leaf
Psywave
Spite
Power Gem

Vivillon
Lvl 100
Iv 31/x/31/31/31/31
Nature: Timid
Ability: Shield Dust
Item: Insect Plate
Move set:
Bug Buzz
Hurricane
Quiver Dance
Aromatherapy

Talonflame (Flare)
Lvl 75
Iv 31/31/31/31/31/31
Nature: Adamant
Ability: Gale Wings
Item: None
Move set:
Agility
Acrobatics
Brave Bird
Roost

Xatu
Lvl 72
Iv 31/31/31/x/31/31
Nature: Jolly
Ability: Magic Bounce
Item: None
Move set:
Confusion Ray
Future Sight
U-turn
Roost

What would make them better as a team?
I am currently working on a Sunflora, Froslass, Slaking, Dusknior and Vespiquen as substitutes for the others.

Thanks!

If you're able, I'd recommend replacing Mismagius for Dusknoir.

From looks of things, Mismagius seems to be a special-attacker, which you already have in such as Alakazam. However, your team lacks a defensive member, which, I believe, Dusknoir would be able to play the role perfectly well! For moves, I would suggest Will-O-Wisp, Substitute, Pain Split, and perhaps Shadow Ball; with combination of these, you would be able to stall your foes pretty heavily, whether it be online or in-game.

Talonflame is looking great! Though, it doesn't seem that it necessarily needs Agility; since yours has Gale Wings, it already gains an upper-hand when using flying-type moves. Instead, my suggestion would be to consider Flare Blitz. Hope this helps!

Thanks :)
I've changed up the Talonflame.
I'll start working on the dusknior now.

The plates are not very good items and I would always advocate having items on every pokemon