Giving Charizard 3 moves of the same type is a bad idea, severely hampering its coverage. Stick to one Fire move, and you're good. And Fly is a bad move to use competitively, as the opponent can switch to something else to take the attack:
-Fire Blast/Flamethrower
-Solar Beam
-Focus Blast
-Roost
Nature: Timid/Modest
EVs: 16 HP/252 SAtk/240 Spe
Item: Charizardite Y
or
-Flamethrower/Fire Blast
-Solar Beam/Focus Blast/Earthquake
-Will-o-Wisp
-Roost
Nature: Calm
EVs: 248 HP/180 SDef/80 Spe
Item: Charizardite Y
Charizard X is viable simply because it focuses more on its physical movepool, due to its Tough Claws ability. It powers up Charizard's contact moves, and Charizard's physical STABs in Flare Blitz, Dragon Claw and Outrage happen to be contact moves that benefit from Tough Claws. For the record, Charizard X's offenses are equal, but its physical prowess is more focused on, and its physical move pool is just as good as its special one. Also, Charizard X is more used than Charizard Y because of its versatility, better defensive typing and lesser dependency on team support. Charizard Y is still viable in its own right, though:
-Dragon Dance
-Flare Blitz
-Dragon Claw
-Roost/Earthquake
Nature: Adamant/Jolly
EVs: 96 HP/252 SAtk/160 Spe
Item: Charizardite X
Ability: Blaze
or
-Flare Blitz/Earthquake
-Dragon Claw/Earthquake
-Will-o-Wisp
-Roost
Nature: Careful
EVs: 248 HP/180 SDef/80 Spe
Item: Charizardite X
Ability: Blaze
or
-Flare Blitz
-Dragon Claw
-Earthquake/Substitute
-Roost
Nature: Adamant
EVs: 40 HP/252 Atk/216 Spe
Item: Charizardite X
Ability: Blaze
or
-Swords Dance
-Tailwind
-Flare Blitz
-Outrage
Nature: Adamant
EVs: 40 HP/252 Atk/216 Spe
Item: Charizardite X
Ability: Blaze
There's little point in investing in Alakazam's defenses, nor is it a good idea to give it RestTalk, simply because Alakazam itself is ridiculously frail. The standard max Special Attack/max Speed spread should be used:
-Psychic
-Shadow Ball
-Focus Blast
-Thunder Wave/Hidden Power (Ice/Fire)/Dazzling Gleam
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Focus Sash
Ability: Magic Guard
Gliscor should run this EV spread: 244 HP/28 Def/224 Spe. This spread lets it outspeed threats up to Jolly Mamoswine.
For Dragonite, Dragon Rush isn't worth using because it's inaccurate. Wing Attack is a weak STAB to turn to. Inner Focus is a very situational ability; Multiscale outclasses it in every way possible, as it helps Dragonite get a Dragon Dance up by halving the damage it takes at full health. Here's a better take on Dragon Dance Dragonite:
-Dragon Dance
-Outrage
-Extreme Speed (+2 priority is neat)
-Earthquake/Fire Punch
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Lum Berry
Ability: Multiscale
Not only is Mega Gengar banned to Ubers, but having 2 Mega Pokemon on the team doesn't do anything. Remember, only 1 Pokemon per player can Mega Evolve per battle. Regular Gengar is still viable:
-Shadow Ball
-Sludge Bomb/Sludge Wave
-Focus Blast/Thunderbolt
-Destiny Bond
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Life Orb
or
-Substitute
-Shadow Ball
-Will-o-Wisp
-Sludge Bomb/Sludge Wave/Focus Blast/Taunt/Disable
Nature: Timid
EVs: 28 HP/148 SAtk/80 SDef/252 Spe
Item: Black Sludge
or
-Hex
-Taunt
-Will-o-Wisp
-Substitute/Sludge Wave
Nature: Timid
EVs: 144 HP/108 SAtk/4 SDef/252 Spe
Item: Black Sludge
Considering that Charizard and Dragonite are weak to Stealth Rock, Rapid Spin and Defog support should be included, as both moves remove Stealth Rock and other entry hazards upon use:
Tentacruel:
-Scald
-Acid Spray
-Sludge Bomb/Knock Off
-Rapid Spin
Nature: Bold
EVs: 252 HP/224 Def/32 Spe
Item: Black Sludge
Ability: Liquid Ooze
Starmie:
-Hydro Pump
-Psyshock/Thunderbolt
-Ice Beam
-Rapid Spin
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb/Leftovers
Ability: Natural Cure
or
-Scald
-Reflect Type
-Rapid Spin
-Recover
Nature: Timid
EVs: 248 HP/20 Def/16 SDef/224 Spe
Item: Leftovers
Ability: Natural Cure
Mandibuzz:
-Foul Play
-Roost
-Whirlwind/Taunt
-Defog
Nature: Bold
EVs: 248 HP/136 Def/108 SDef/16 Spe
Item: Leftovers
Ability: Overcoat
Excadrill:
-Earthquake
-Iron Head
-Rock Slide
-Rapid Spin
Nature: Jolly/Adamant
EVs: 252 Atk/4 Def/252 Spe (Jolly) or 120 HP/136 Atk/252 SDef (Adamant)
Item: Choice Scarf (Jolly)/Assault Vest (Adamant)
Ability: Mold Breaker
Latios:
-Draco Meteor
-Psyshock
-Surf/Thunderbolt/Hidden Power (Fighting)
-Defog
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb
Stealth Rock is a very important entry hazard in competitive play because it helps achieve OHKOs/2HKOs. Here are examples of Pokemon that can set Stealth Rock for you:
Therian Landorus:
-Stealth Rock
-Earthquake
-Stone Edge/Rock Slide/Knock Off
-U-turn
Nature: Impish
EVs: 252 HP/248 Def/8 Spe
Item: Leftovers
Ferrothorn:
-Stealth Rock
-Leech Seed
-Power Whip
-Gyro Ball/Protect/Knock Off
Nature: Relaxed
EVs: 252 HP/88 Def/168 SDef
Item: Leftovers
Ability: Iron Barbs
Garchomp:
-Stealth Rock
-Outrage/Dragon Claw
-Earthquake
-Fire Blast/Swords Dance
Nature: Naive/Jolly
EVs: 252 Atk/4 SAtk/252 Spe
Item: Life Orb/Focus Sash/Rocky Helmet
Mamoswine:
-Stealth Rock
-Ice Shard
-Earthquake
-Endeavor/Icicle Spear
Nature: Jolly
EVs: 252 Atk/4 Def/252 Spe
Item: Focus Sash
Ability: Oblivious