Hello AJ34 and nice team :)
I found a weakness to ground moves, indeed, your team haven't any immunity to ground and two your pokčmon (Terrakion and Jirachi) are weak to it.
I'd use Landorus in place of Mamoswine with a particular moveset that I will put in this response later. Then,
I'd use Choice Scarf Jirachi in place of your current Jirachi because it's a really good revengekiller with its coverage (I would not use Choice Scarf Keldeo here because I think that your team needs a strong special sweeper and Calm Mind Keldeo does its work very well).
Finally, I'd use Hidden Power Ice in place of Clear Smog on your Amoonguss because I think that Clear Smog is quite useless here and Hidden Power Ice is nice to hit Landorus and dragon types.
Landorus set:
...

Landorus (M) @ Focus Sash
Trait: Sheer Force
EVs: 4 HP / 252 SAtk / 252 Spd
Timid Nature (+Spd, -Atk)
- Stealth Rock
- Earth Power
- Focus Blast
- Hidden Power [Ice]
Hope I helped, good luck!
~Alexander