Help with my team please

[Kris]

Now whoever told you Swords dance Scizor sucks is wrong. Swords Dance Scizor is amazing. Mega Scizor is unbelievably strong thanks to an Ability called Technician boosting the power of moves with 60 Power or less. First up, Bug Bite, for a lack of a better term, sucks. It gets boosted by Technician but it's competitive use is very lackluster. Stealing Berries is more a maingame thing tbqh. Have you heard of U-Turn? U-Turn is a move that Scizor can use to damage an opponent and switch out to a different Pokemon. For example, you can U-Turn on say, Torkoal who would use Eruption, switch into Swampert to tank the hit. U-Turn is a very useful attack and you want to replace Bug Bite for this. Aerial Ace is also not needed on Scizor as it doesn't get STAB from it and a much better option exists. Defog clears any hazards on your side of the field like Stealth Rock, Spikes and Sticky Web. Swap Aerial Ace for Defog or Swords Dance. Finally Bullet Punch and Roost can stay.Nature will want to be Adamant. EVs for this set are as follows: 64 Attack to 2HKO non-defensive Zygarde with Bullet Punch, 248 Hp and 120 Defense EVs to optimize Mega Scizor's bulk, 16 Special Defense EVs to avoid +1 Magearna's Thunderolt from being a 2HKO and 60 Speed EVs to outspeed and U-Turn on Assault Vest Magnet Pull Magnezone.

As best girl @FireTaco said, swap Psychic for Flash Cannon on Lucario and I'll add on telling you to give it Steelium Z.

Ttar looks A-Ok

Baton Pass is banned in OU, so give it Psyshock which hits Chansey better because Psyshock targets the opponent's Defense and not Special Defense, Shadow Ball over Psychic, give it a Focus Sash and a Timid Nature.

Gengar's Ability is Cursed Body. You want to put 252 EVs to Special Attack because Gengar needs to as much damage as possible. Instead od Destiny Bond, give it Will-o-Wisp. Air Balloon makes Gengar immune to Ground type moves and is kind of like a fake Levitate, so consider that.

Hope it helps

[Jericho]

Thanks for the web link FireTaco. Thank you to all, I have taken all of your advice into consideration. 
I understand about scizor but he is A late game sweeper so I think I'll keep Aerial Ace

I took some time to look at that website, here is what I came up with for the OU Tier:

Tyranitar: Ability - Sandstream, Nature - Sassy, Ev's - 252 HP, 76 Atk, 180 SP Def, Hold Item - Assult Vest
Stone Edge, Ice Beam, Crunch, pursuit 

Salamance: Ability - Moxie, Nature - Jolly, Ev's - 252 Atk, 4 Def, 252 Speed, Hold Item - Flyinium Z
Dragon Dance, Fly, Dragon Claw, Earthquake 

Scizor: Ability - Technician, Nature - Adamant, Ev's - 248 HP, 64 Atk, 120 Def, 16 SP Def, Hold Item - Mega Stone
Ariel Ace, Defog, Bullet Punch, Roost

Kingdra: Ability - Damp, Nature - Modest, Ev's - 4 HP, 252 Sp Atk, 252 Speed, Hold Item - Dragonium Z
Surf, Draco Metero, Ice Beam, Flash Cannon

Heatran: Ability - Flash Fire, Nature - Timid, Ev's - 252 SP Atk, 4 SP Def, 252 Speed, Hold Item - Groundium Z
Magma Storm, Earth Power, Toxic, Stealth Rock

Gengar: Ability - Cursed Body, Nature - Timid, Ev's - 4 HP, 252 SP Atk, 252 Speed Hold Item - Life Orb
Shadow Ball, Sludge Bomb, Hex, Will-o-Wisp

I also made A UU team I'll post later. Just in case I wanna switch things up

[Spyro190]

- Aerial Ace sucks. It doesn't make MScizor a late game sweeper, it's just a wasted slot.
- Technician as both preMEvolution and postMEvolution ability is a waste: Light Metal at least helps if you switch on Low Kick.
- Kingdra need Swift Swim and a teammate with Drizzle to be useful.
- You should get rid of Hex and use Focus Blast, which is the perfect coverage move for Shadow Ball.
- Use just one Z crystal: all the others will be wasted item slots.

[Jericho]

So I edited my team for the last time, how bout this

Tyranitar: Ability - Sandstream, Nature - Sassy, Ev's - 252 HP, 76 Atk, 180 SP Def, Hold Item - Assult Vest
Stone Edge, Ice Beam, Crunch, pursuit 

Garchomp: Ability - Rough Skin - Nature - Naive, Ev's - 4 HP, 252 Atk, 252 Speed, Hold Item - Life Orb
Swords Dance, Earthquake, Dragon Claw, Fire Blast

Mega Scizor: Ability - Technician, Nature - Adamant, Ev's - 252 HP, 108 Atk, 148 Speed, Hold Item - Mega Stone
U-Turn, Defog, Bullet Punch, Roost

Keldeo: Ability -  Justified, Nature - Hasty, Ev's - 252 SP Atk, 4 SP Def, 252 Speed Hold Item - Choice Scarf
Hydro Pump, Secret Sword, Stone Edge, Taunt

Heatran: Ability - Flash Fire, Nature - Timid, Ev's - 252 SP Atk, 4 SP Def, 252 Speed, Hold Item - Groundium Z
Magma Storm, Earth Power, Toxic, Stealth Rock

Gengar: Ability - Cursed Body, Nature - Timid, Ev's - 100 HP, 156 SP Atk, 252 Speed Hold Item - Air Ballon
Shadow Ball, Sludge Bomb, Focus Blast, Destiny Bond

I will use the other evs that were mentioned above in any case. But I though speed to outspeed some of his threats for mega scizor