the team looks good on paper but in practice , it has certain gaps to fill in
1: As rightly pointed out by others , you do not have a water resist.
possible solutions : using slowbro or slowking over corvi
use the defensive lando set and give lando defog over stealth rock , and give heatran stealth rock over toxic for flash cannon.
I would advice to use slowbro , since you already have blissey as a specially defensive wall.
I personally recommend the following set :
Slowbro @ Heavy-Duty Boots
Level: 100
Relaxed Nature
Ability: Regenerator
EVs: 252 HP / 252 Def
IVs: 0 Atk
- Ice Beam/Slack off / Flamethrower
- Scald
- Teleport
- Future Sight
It is the standard slowbro set , ice beam for lando , torn and garchomp and flamethrower to catch ferro off guard , or you can go with slack off to heal . Future sight with psychic terrain support is really helpfull to put holes in enemy defence , and teleport for momentum
2. Nothing on the team can reliably check dragapult , blissey can check specs dragapult but can do nothing in return since it does not have toxic ,
on the other hand blissey losses to dd dragapult , so i would suggest using toxic on blissey , and make give lando more def evs since you already have blissey