Mega Camerupt has no use for Heat Wave, except in doubles. Fire Blast is the superior option in singles:
-Fire Blast
-Earth Power
-Ancient Power
-Will-o-Wisp/Stealth Rock
Nature: Modest
EVs: 168 HP/252 SAtk/88 Spe
Item: Cameruptite
Ability: Solid Rock
Flygon is better off as a physical attacker; its Special Attack is very mediocre:
-Earthquake
-Outrage
-U-turn
-Defog
Nature: Jolly
EVs: 252 Atk/4 SDef/252 Spe
Item: Choice Scarf
Mega Aggron is normally the better option over regular Aggron, due to its increased bulk, mono-Steel typing and Filter, but regular Aggron still has a (small) niche in abusing recoil-less Head Smashes:
-Heavy Slam/Iron Head
-Head Smash
-Earthquake/Low Kick
-Ice Punch
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Choice Band
Ability: Rock Head
or
-Rock Polish/Autotomize
-Heavy Slam/Iron Head
-Head Smash
-Earthquake
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Life Orb
Ability: Rock Head
The lack of STAB on Mightyena seriously hurts. The elemental fangs are very weak outside of very specific targets. IMO, Crobat should be the better option because not only is it used by villain teams, but it provides stall breaking utility:
-Brave Bird/Acrobatics
-U-turn/Toxic/Taunt
-Defog/Taunt
-Roost
Nature: Jolly
EVs: 248 HP/60 Def/200 Spe
Item: Black Sludge/none
Ability: Infiltrator
or
-Brave Bird
-U-turn
-Cross Poison/Defog
-Sleep Talk/Defog
Nature: Jolly
EVs: 252 Atk/4 SDef/252 Spe
Item: Choice Band
Ability: Infiltrator
Zangoose should stick to 4 attacks + Toxic Orb, as it needs Quick Attack to make up for its not-so-outstanding Speed. Fire Punch also doesn't hit anything notable that Close Combat can't:
-Facade
-Close Combat
-Knock Off
-Quick Attack
Nature: Jolly
EVs: 252 Atk/4 SDef/252 Spe
Item: Toxic Orb
Ability: Toxic Boost
Sun is rather easy to eliminate, given that Politoed, Tyranitar and Hippowdon are somewhat common. RestTalk should be used to preserve Ninetales:
-Flamethrower
-Will-o-Wisp
-Rest
-Sleep Talk
Nature: Calm
EVs: 248 HP/120 SDef/136 Spe
Item: Heat Rock
Ability: Drought