First ever sun team for doctor FLAME?!?!!? Well! Let's make it a good one!
As said in the comments, HP water will be useless in the sun, doing about 35 BP. XD
If you want something to take care of other fire types, you could try HP ground, but what I'd suggest would be Will-O-Wisp, to cripple physical attackers and keep you safe from physical attacks, seeing that ninetales doesn't have the greatest physical defense. Other than that, if you were willing you could take out flamethrower and put in Fire Blast, but that's up to you. Otherwise, good lead.
Looks good, he's a popular guy for the job of getting in entry hazards. However, being that you're in the sun, no matter how bulky Forretress is, fire will kill him. Keep it in mind when you're thinking about using volt switch, that you're probably not the faster Pokemon. Otherwise, good set.
Good set, just keep in mind that Scald isn't going to be as powerful as you think because of the sun. I'm assuming your main purpose for scald is to burn. He looks pretty powerful, and specs can really damage the opponent.
Two words: Life Orb. Darmanitan takes NO recoil damage from the life orb because of his ability Sheer Force. This way you can also use your different moves. Speaking of moves, Hammer Arm? Try superpower. Chances are you're going to switch out Darmanitan after you use Hammer Arm because of his speed loss. So why not make it more powerful? Also, U-turn is a very good move, so, probably instead of stone edge. (Blegh, horrible accuracy)
Yeah, this guy is used all the time. Leftovers? Try Black Sludge. People always forget Venesaur is part poison. Since you already have lots of grass type attacks, you could switch energy ball for Sludge Bomb, and if you wanted, HP fire. This guy looks good.
Can't say I know much about this guy. Looks good if you ask me, but you might want to throw in Aromatherapy if you're looking to heal your pokemon. This guy also has plenty of weaknesses, so be weary... Best of luck to you and those of you on your sun team!!!