Ninetales is the weather starter who's the hardest to keep alive, given its vulnerability to Stealth Rock and average stats bar Special Defense and Speed. It's better with defensive sets normally, but it can pull offensive ones somewhat well, though it needs something other than Life Orb:
-Flamethrower
-Will-o-Wisp
-Sunny Day
-Roar/Hypnosis/Substitute
Nature: Timid
EVs: 252 HP/120 Def/136 Spe
Item: Leftovers
Ability: Drought
or
-Sunny Day
-Fire Blast
-SolarBeam
-Hidden Power (Ice)/Will-o-Wisp/Nasty Plot
Nature: Timid/Modest
EVs: 252 SAtk/4 SDef/252 Spe
Item: Leftovers/Air Balloon
Ability: Drought
U-turn needs to go over Stone Edge on Infernape so that it has a scouting option.
Dark Pulse is redundant with Chandelure's Ghost STAB. As a rule of thumb, never use Ghost and Dark offensive moves together unless it's for utility purposes (Spiritomb does so to trap opposing Psychics/Ghosts). Hidden Power (Fighting) or Trick needs to go in its place, the former for hitting Tyranitar and Heatran hard and the latter to cripple walls.
While Petaya Berry is an interesting option on Volcarona, it's really not needed, IMO. Since you're using Roost, a bulky spread is preferred:
-Quiver Dance
-Fire Blast
-Bug Buzz
-Roost
Nature: Timid
EVs: 240 HP/252 Def/16 Spe
Item: Leftovers
Offensive Volcarona uses:
-Quiver Dance
-Fire Blast/Fiery Dance
-Bug Buzz
-Hidden Power (Rock/Ground)/Giga Drain
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb/Lum Berry
Or, if you feel rather gutsy, you can opt for ChestoRest. This set is meant to set up as many Quiver Dances as you can, heal off the damage/status wtih Rest, then sweep:
-Quiver Dance
-Fire Blast/Fiery Dance
-Bug Buzz
-Rest
Nature: Modest
EVs: 160 HP/236 SAtk/112 Spe
Item: Chesto Berry
Darmanitan is a better alternative over Arcanine, IMO, since its Sheer Force ability, in conjunction with sun, makes Flare Blitz an insanely powerful move:
-Flare Blitz
-U-turn
-Rock Slide
-Superpower/Earthquake
Nature: Jolly/Adamant
EVs: 252 Atk/4 SDef/252 Spe
Item: Choice Scarf/Choice Band/Life Orb
Ability: Sheer Force
Since Heatran is using a defensive set, Lava Plume is the better option over Fire Blast because Fire Blast's low PP hurts it in the long run, plus Lava Plume has a nice chance of burning the opponent. I don't see much use of Sub in defensive sets at all. Heatran is also better with a specially defensive spread as most of its resists come from the special end and physically defensive Heatran still takes loads from Earthquake regardless:
-Lava Plume
-Stealth Rock/Roar
-Protect
-Toxic/Will-o-Wisp/Earth Power
Nature: Calm
EVs: 248 HP/252 SDef/8 Spe
Item: Leftovers
Ability: Flash Fire
I will take these suggestions into consideration and just asking why should I have Sunny Day on Ninetales when I have Drought?