Whimsicott @ Focus Sash
Ability: Mischievous Heart
Nature: Timid
252 Def / 252 Spd / 4 Atk
~ Encore / Taunt
~ Leech Seed
~ Substitute(idk if this is good here but if another move is suggested ill probably use that.)
~ U-turn
This would be my lead. the ability lets me set up/not let them set up.
Whimsicott is doing no damage with U-turn, and since non-attacking moves give it priority, investing in speed just to predict switches, when Substitute already does the same thing but with priority, you do NOT want U-turn. What Whimsicott does best is switching into enemy sweeper to encore a stat-up move, set up a Substitute, and Leech Seed away. You've got the right idea with Taunt, but any other poke with Prankster (you can stop using the japanese names for abilities, ya know. =P) can do what this Whimsicott is trying to do, better. You should take off U-turn and the Speed EVs, replace it with something epic like Tailwind since it's leading, Light Screen to further bolster your team's defenses; if you dump your speed EVs into Def, this is a great idea for Whimsicott alone, too. Or you can do the opposite and make Whimsicott specially bulky, and have it use Cotton Guard, which increases it's defense by 2.5. This makes it frighteningly bulky towards any physical attacker, which can let you start SubSeeding, and force it out.
Also, OHKOing Whimsicott is no easy task, especially if you preemptively use Substitute, or invest in it's HP and either stat. If you use Light Screen or Cotton Guard respectively, you'll be impossible to OHKO unless you're taking a Specs Heatran Eruption to the face or something, lol (no, there's no such lead Heatran that does that xD). Point being, replace your Sash with Leftovers. Leech Seed & Leftovers makes SubSeeding a viable strategy, and gives it extra bulk, instead of surviving some overpowered attack it shouldn't be staying in on no matter what. It's not a suicide lead, so no Sash should be used.
And, if you don't want to change Whimsicott at all, you might as well grab Thundurus or Tornadus in it's stead, since they both have Prankster and Taunt, Thundurus has T-wave for status, and they both hit very hard.
Kyurem @
Ability: Pressure
Nature: Naive
4 Hp / 252 SpAtk / 252 Spd
~ Blizzard
~ Focus Blast
~ Psychic
~ Dragon Pulse/Flash Cannon/ Shadow Ball
My friend used this Kyurem, i had a very hard time taking it down, it almost took me down...
You really don't want Blizzard, lol. Ice Beam all the way. If Psychic is there to take down Fighting types, be careful when using it. Kyurem isn't going to outspeed the fastest and deadliest fighting types, especially ones with a Scarf. So it's an "on the switch" move only.
Also, I'm curious. Are you aiming at anything in specific that hurts Kyurem with Focus Blast? Steel types in general, sure, but you might want to make room for Glaciate. With max speed, nerfing a pokemon's Scarf almost guarantees that Kyurem will outspeed after a Glaciate, which functions similar to Substitute in that you can pick the move you want after the switch; the plus though is that you're still doing huge damage (90 BP and 356 Sp.A is no joke, even more so if you used a Life Orb or somethin'), and then you can do even higher damage. You'd be surprised how much a -1 speed on the foe can impact how they can counter Heatran. For example, unless a Scarf Terrakion is running Max speed with a neutral nature, you can go ahead and finish it off with Psychic. I've no idea how many Scarf Terrakions do or don't run max speed, but that was just an example of Glaciate's uses.
As for the item, with a Taunt lead, stopping those rocks from getting up is 100% necesarry if you want to maximize this beast's power and use Specs or a Life Orb. Since you're using Naive, the huge boost in power would be sorely appreciated.
Victini @ Wide Lens
Ability: Victory Star
Nature: Modest
8 Hp / 252 SpAtk / 248 Spd
~ Thunder
~ FireBlast
~ Energy Ball
~ Psyshock/Psychic
Well i love Victini's ability and combine it with wide lens=wicked combo and makes thunder and fireblast rarely miss
Sorry to say, but this just isn't worth it at all... Fire Blast has perfect accuracy, sure, but Thunder still only has 84%. Ya see, Victory Star and Wide Lens increase the base accuracy of a move by 10%, both being stackable. 70% gets increased by 7% twice, so... yeah. Since Victini is very slow for this set, and 328 Sp.A really isn't anything special, it's underwhelming. Give it a life orb and it's perfect accuracy moves, and it'l definitely do plenty more damage. Unless that 30% burn and paralysis chance is somethin' special to ya, a poor set indeed.
And, as another note, I personally feel that Victini ain't worth using unless you intend to abuse Sunlight, V-Create, or both. Using a physical Scarf/Band set with V-Create is much more potent for Victini, sun or not. If you don't have access to the movie Victini, that's sadly not an option, 'course. I know ya said you like him the way he is, but is really isn't a good set, and Victini can be used in a much better way, so yeah.
Jellicent @ Leftovers
Ability: Water Absorb
Nature: Bold
60 Hp / 200 Def / 52 SpAtk / 200 SpDef
~ Toxic
~ Shadow Ball
~ Surf
~ Energy Ball/Psychic
Jellicent is there to cover my weaknesses and possibly stall... i might change ev's and moves a little bit around, suggestions...
You're using 2 EVs too many, ya know. 
Standard Jellicent, all good. Nothing I should bitch about. You should definitely use Energy Ball, IMO.
Terrakion @ Life Orb
Ability: Justified
Nature: Adamant
4 Hp / 252 Atk / 252 Spd
~ Sword dance
~ Stone Edge
~ Earthquake
~ Sacred Sword
He's my physical sweeper i took my friend on with just him sweeped almost his entire team(his team was beastly almost didnt win lol)
Swords Dance Terrakion is definitely scary, no denying that. Not having the ability to ruin things with Close Combat sucks, but with double attack, Sacred Sword'll do, lol. You really need a Jolly nature, though. 315 Speed ain't outspeeding much. And considering Terrakion's plenty common weaknesses and while it isn't frail, without investment it's not going to take many hits. It needs that extra speed, and DOESN'T need that extra attack Adamant offers. Adamant should be the exclusive nature for Scarf sets, IMO. Unfortunately, the fact you can't just change natures leaves you boned, really...
Also, Ground and Fighting moves are terrible to use together, horrible synergy. You should replace EQ with X-scissor ASAP, to stop bulky psychics like Reuiniclus or a faster one like Latios from stopping your sweep cold. Sweepers with SD don't need high-power moves, they need as much coverage to help their sweep as possible.
Theres my team so far. I cant think of any pokemon for that last spot... any recommendations? Terrakion im not looking to change.(hes shiny

and i love him), Victini im not looking to change i like him just the way he is. Jellicent is okay but just tell me what u think. and Kyurem i think is fine but if u have suggestion let me know!
For the last slot, I can't think of anything epic off the top of my head, but you need a bulky Steel type for this team ASAP. No resists to Ghost, Dragon, or Flying, and I feel your Rock weakness isn't covered enough. Make sure this Steel type won't be hit super effective by Fighting or Ground, though; otherwise you're risking your team being very susceptible to the most common of physical sweeper; the very Terrakion you're using could sweep your entire team if it beats out yours in a speed tie, as it is.
Thanks HomieG.