I'm glad that you're inspired to use my team, but don't copy it (almost) completely. Just saying, copying isn't good, if not pointless, when you don't even know how the team is supposed to work. It's better to experiment things for yourself before asking for advice.
What's the point of Bisharp having an Adamant nature when its Attack isn't being invested in at all? Use max Attack/max Speed (4 HP/252 Atk/252 Spe). Bisharp also appreciates the extra power from Black Glasses, Dread Plate, or Life Orb, or the status-curing utility of Lum Berry. Despite its mediocre bulk and common weaknesses (no good player would leave Bisharp in on Fire, Ground, or Fighting Pokemon, unless they're weakened into Sucker Punch range), Bisharp has a good set of resistances to compensate.
Offensive Therian Landorus gets more milage out of Speed than in bulk. 72 HP/252 Atk/184 Spe is enough to let it outspeed threats up to +Speed Dragonite and Mega Altaria.
Absol isn't a bad Mega by any means, but both it and Bisharp share a bad weakness to Fighting (Absol is frail, while Bisharp is 4x weak to it, despite its good Defense). Use Mega Gardevoir or Mega Gallade to compensate for this.
Gardevoir:
-Psyshock
-Hyper Voice
-Focus Blast
-Calm Mind/Will-o-Wisp/Taunt
Nature: Timid/Modest
EVs: 24 Def/232 SAtk/252 Spe
Item: Gardevoirite
Ability: Trace
Gallade:
-Swords Dance
-Zen Headbutt
-Close Combat/Drain Punch
-Knock Off/Shadow Sneak/Ice Punch
Nature: Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Galladite
Latios makes better use of an all-out offensive spread, so Latias is better off with a bit more bulk: 72 HP/184 SAtk/252 Spe lets it avoid the 2HKO from Life Orb Thundurus' Hidden Power Ice.
Sylveon having Moonblast is pointless when it has access to Pixilated Hyper Voices:
-Hyper Voice
-Psyshock (allows it to hit Poison Pokemon on the switch)
-Hidden Power (Fire/Ground)/Shadow Ball
-Baton Pass
Nature: Modest
EVs: 244 HP/252 SAtk/12 Spe
Item: Choice Specs
Ability: Pixilate
As some people mentioned in my team thread, Talonflame may not be necessary, and you might need a way to get your attackers in safely, or to slow faster threats down with Electric Pokemon. Wash Rotom or Thundurus are safe picks for this. They also deal with Mega Slowbro:
Wash Rotom:
-Volt Switch
-Hydro Pump
-Will-o-Wisp
-Pain Split
Nature: Bold
EVs: 248 HP/252 Def/8 Spe
Item: Leftovers/Chesto Berry
Thundurus:
-Thunderbolt
-Hidden Power (Ice)/Grass Knot
-Focus Blast/Grass Knot
-Thunder Wave
Nature: Timid
EVs: 4 Def/252 SAtk/252 Spe
Item: Life Orb/Leftovers
Ability: Prankster