With Roserade I see no reason not to run max speed, some speed natured base 90s will out speed you with your current EV spread, whereas if you just max it then you still have a chance to speed race them to determine who goes first.
Also i'd like to say i personally dont like Leaf Storm on Roserade, all of the pokemon you meantioned that you can hit with it are hit from Grass Knot with 120 Base Power which also gives you the option of attacking again due to no Special Attack drop. And as for your last slot i'd go with Toxic Spikes as in comparison with normal Spikes they take a shorter time to set up and can have a more devastating effect with just one layer down.
As for Swampert, i'd rather go with Surf for the sheer fact that i hate to miss attacks in a possibly dire situation. Those Special Defence Evs you have can possibly be shifted to Special Attck if you still want Surf to do a bit more damage.
For Gengar i'd simply just use Modest, not much pokemon that fast are going to be using Scarf so i'd say your pretty safe going with a Special Attacking nature.
I can see your team having Gyarados issues, so i'll say in that slot that you have Taunt on Heatran i'd replace it for Hp Electric as it will nearly OHKO Gyarados and gives you some better coverage against Water types like Starmie. Leftovers would also be my item of choice here.
Personally i like Hitmontop but i think this set leaves something to be desired, its a decent attacker but in terms of your moveset i'd simply rather go with Stone Edge over Bullet Punch, the low Base Power honestly isnt worth it when your just hitting Gengar. Stone Edge will nearly ohko Gengar as well as give you coverage against Gyarados and Salamence.
Lucario is probaly ok but with the popularity of Cresselia and Dusknoir i'd simply rather have Crunch over one of your priorety attacks, Extremespeed hits harder than Bullet Punch but Bullet Punch after the Swords Dance does get the OHKO on gengar so i'd actually probaly replace Extremespeed for Crunch. It will also hit Gliscor for the same Base Power as Extremespeed and also has the chance for the defense drop.