Help me pick a Mega for my team?

[SCf3]

I'll test out Landorus for now and see how it goes. :p Here's my updated team.

Sylveon (F) @ Choice Specs
Ability: Pixilate
Level: 50
EVs: 56 HP / 252 Def / 200 SpA
Modest Nature
IVs: 0 Atk
- Hyper Voice
- Moonblast
- Return
- Shadow Ball

Kato (Raichu) (M) @ Focus Sash
Ability: Lightning Rod
Level: 50
Shiny: Yes
EVs: 28 HP / 4 Def / 220 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Fake Out
- Thunderbolt
- Grass Knot
- Protect

Fishy (Milotic) (M) @ Sitrus Berry
Ability: Competitive
Level: 50
Shiny: Yes
EVs: 54 HP / 40 Def / 162 SpA / 252 SpD
Modest Nature
IVs: 0 Atk
- Scald
- Ice Beam
- Safeguard
- Recover

Sword Thing (Aegislash) (M) @ Leftovers
Ability: Stance Change
Level: 50
EVs: 236 HP / 252 SpA / 20 Spe
Modest Nature
IVs: 0 Atk
- King's Shield
- Shadow Ball
- Flash Cannon
- Substitute

Mawile (F) @ Mawilite
Ability: Intimidate
Level: 50
EVs: 252 HP / 180 Atk / 40 Def / 36 SpD
Adamant Nature
IVs: 24 SpA
- Play Rough
- Sucker Punch
- Iron Head
- Protect

Flying Thing (Landorus-Therian) @ Choice Scarf
Ability: Intimidate
Level: 50
Shiny: Yes
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Earthquake
- Rock Slide (originally had Stone Edge bc Landorus could attack if Wide Guard was up. We'll see how this goes.)
- U-turn
- Substitute