Hey MewCreation I give you my welcome back to this site! You seem to be a very active battler, so we're glad to have you!
Let me help you out here.
Heatran (Phazer) > Bronzong: Doing little for the team other than putting up a layer of Rocks, this guy has no real Role on the team. However, you know have both a Pokemon who can launch SR's and Phaze at the same time. He also forms an infamous Defensive Core that is capable of checking both Sand and Sun threats with unexpected ease. Ask Kyron (Pokewatt) how annoying the two are together lol
Heatran (F) @ Leftovers
Trait: Flash Fire
EVs: 252 HP / 4 SAtk / 252 SDef
- Lava Plume
- Earth Power
- Stealth Rocks / Protect
Simple Phazer set.
Forretress > Tentacruel: As I am suggesting Heatran, an additional Ground Type Weakness, replacing Tentacruel with the best Hazard Setter in the game that also symergizes with the rest of the team well is a good idea. By embracing the single Fire type weakness, the opponents options almost always are guaranteed to be decisively checked.
Forretress @ Leftovers
EVs: 252 HP / 252 Def / 4 SDef
- Volt Switch
- Gyro Ball
- Stealth Rocks
- Toxic Spikes
It doesn't hurt to have an additional SR setter just in case they are spun away, but if you feel you only need one, then add Protect > SR on Heatran. This guy also gives access to Safe Switch-Ins with slow Pivot move
Gyarados. (Sub MoxieDos) > Jellicent: The team enjoys a clean up sweeper that can also take Ice, Water, and Fighting type attacks for the rest of the team. MoxieDos is your man.
Gyarados (M) @ Leftovers / Water Gem
EVs: 144 HP / 108 Atk / 252 Spd
Jolly Nature (+Spd, -SAtk)
- Dragon Dance
Bulky enough to set up sub with the natural strength to activate Moxie and pick up momentum easily. However, if you guarantee tge initial Moxie boost, go for Water Gem.
Choice Scarf Latios >Life Orb Latias >Latias (current): Even though this is a Stall based team. I suggest reserving a spot for a decent Choice Scarfer to score KO's on weakned enemies while elimination fast threats swiftly. An ideal Pokemon is Choice Scarf Latios, who's Speed is unrivalled (as a Scarfer) with wide coverage options.
Latios (M) @ Choice Scarf
EVs: 4 HP / 252 SAtk / Spd
Timid Nature (+Spd, -Atk)
- Dragon Pulse / Draco Meteor
- Surf / Thunderbolt
- Sleep Talk
Simple Scarf Latios that revenge kills clean and picks up momentum easily on a weakened team. Also your much needed Spore absorber and Breloom counter.
I realize that I basically changed the team, but I still hope I helped.