[ORAS] Need help with battle spot doubles team.

[AttilatheFun87]

I mostly play battle spot singles so I thought it would be fun to build a doubles team. So I'm looking for any suggestions for a last pokemon and any other obvious changes that should be made. Please keep in mind this is just for fun on battle spot I'm not looking for a super competitive build.
edit: I didn't notice until just now that I have so many crossover weakness' but like I said before I'm open to changing some stuff around.

Mawile-Mega @ mawilite
Ability: Huge Power
Level: 50
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Sucker Punch
- Play Rough
- Iron Head
- Protect

Jellicent @ leftovers
Ability: Cursed Body
Level: 50
EVs: 252 HP / 4 SpA / 252 SpD
Sassy Nature
IVs: 0 Spe
- Scald
- Will-O-Wisp
- Recover
- Trick Room

Cresselia @ rockyhelmet
Ability: Levitate
Level: 50
EVs: 248 HP / 4 Atk / 8 SpD
Relaxed Nature
IVs: 0 Spe
- Psychic
- Ice Beam
- Trick Room
- Protect

Tyranitar @ assaultvest
Ability: Sand Stream
Level: 50
EVs: 252 HP / 252 Atk / 4 SpA
Naughty Nature
- Crunch
- Rock Slide
- Low Kick
- Ice Beam

Heatran @ safetygoggles
Ability: Flash Fire
Level: 50
EVs: 252 HP / 252 SpA / 4 SpD
Modest Nature
- Heat Wave
- Flash
- Earth Power
- Protect