OK:
- Hitmontop seems alright to me - Dig/Toxic work well in combination, Fake Out's almost always handy to have and Brick Break can smash through Reflect/Light Screen well enough. This set may have trouble killing stuff, but otherwise it's OK. Watch out for Gengar though - you have no means of damaging it. Another thing of note is that, if I remember correctly, Hitmontop can learn Rapid Spin, which is definitely well worth having in a generation where entry hazards rule the roost.
- Salamence CAN use Roar, however it doesn't work too well in combination with its Intimidate ability, which drops a target's Attack stat for you anyway. Dragon Rush is inferior to Dragon Claw and most notably Outrage due to its unreliable accuracy, Fire Blast will probably serve better than Flamethrower on a Dragon Dance set due to the former's 120 Power vs the latter's 95, and Earthquake is a great option in place of Roar to grant you perfect coverage.
- Pain Split or Rest is best in place of Dream Eater for Dusknoir. Overall, I find that Night Shade tends to outdamage Shadow Punch on a primarily defensive EV spread, so if you have 0 EVs in Attack then Night Shade is a better option. Brick Break over Rock Slide again, grants you perfect coverage. Will-O-Wisp is pretty standard, so it can stay.
- Infernape really needs Nasty Plot over Calm Mind here, although it can only get Nasty Plot as a Chimchar - you may need to re-breed for this. Also, Special Fire-type attacks tend to work better than Physical ones on Infernape due to the heavy abundance of Steel-types that have higher Defense than Sp.Defense, and moves like Fire Blast will hit these Pokemon a lot harder than Flare Blitz would.
- Electivire's fine as it is.
- Ice Shard over Blizzard for Mamoswine is probably the best direction to go, and Stone Edge will beat AncientPower in terms of Stone Edge's raw power vs AP's over-reliance on haxy stat boosts. Watch who you set up Stealth Rock against - Mamoswine's defensive typing is a bit crap and he can be killed quite easily if you're careless.
Finally, you also missed out what items your team are using - we'll need to know those as well to progress here.