Well I looked at your team, and I didnt see any weaknesses since they have the same type.
So to awnser your questions:
Bulk: Ok well for me Dragonite has better bulk with Multiscale and can survive to get a DD up. Then proceed to sweep. Only things like blizzard stand a chance against this deadly fighter.[Screw you Abamosnaw.] Salemance, not really but you can make Salemence Special and give it Imtimidate to lower attack. So if you send in Salemance against like a Lucario which is a physical attacker, you can use Imtimidate to use a status move.Maybe Wish so you can be ready to heal. Unfrotunatly it doens't have a good stat raisng move besides DD. Of course you could Dragon Dance while you'r opponent switches out, but Moxie is better.
Surviving Again the awnser is Dragonite. Dragonite has a base 100 sp.def and 95 def, which compared too Salemance's 80 sp.def and def, Dragonite's bulk is better. I was like, oh, that's why its so bulky even with Multiscale broken!
Weather Counter How many awnsers will Dragonite be the winner of? I think Dragonite is better, because with A STAB hurricane and Thunder, that confuse+paralyze chance will make your opponent flee. And you could make this special and give this Flamethower to abuse the sun. Oh my gosh! It can even abuse the hail with a Blizzard. HELP.
Ok for the movesets.
If you want a special rain abuser. My set for Dragonite:
EVs: 252 SAtk / 252 Spd / 4 SDef
- Dragon Pulse
3 moves that abuse rain, Dragon Pulse is for STAB and is quite powerful.Surf is powerful in rain, and Hurricane is a powerful move with STAB and that confuse rate is nice. Same goes for Thunder.
But physical attacker is used more, so...
Dragonite @ Leftovers/Lum Berry
EVs: 252 Spd / 252 Atk / 4 HP
- Dragon Dance
- Dragon Claw/Outrage
- Fire Punch
You should know this set so I'll move along.
I felt like capping, wont do that again.
Ok the special attaker:
@ Life Orb/Choice Specs
EVs: 252 Spd / 252 SAtk / 4 SDef
- Draco Meteor
- Fire Blast
- Hidden Power [Electric]
- Hydro Pump
The godly power, I dont feel like explaining this. Batterys gonna run out. xD
The physical sweeper.
Salamence @ Life Orb
EVs: 252 Spd / 252 Atk / 4 SDef
- Dragon Claw
- Dragon Dance
- Fire Fang
My excuse is up there.
So personaly I would choose Dragonite. Hoped you like this!