Issues with the team:
1. Too many megas
2. Lots of type overlap
3. No support at all
4. Extremely weak to Fairy types
These are my changes
Infernape
I switched Drain Punch for Close Combat, as Infernape isn't lasting long anyways and wants the extra power.
Mega Atlaria
I honestly doubt if this thing is viable, but you said it was one of your main stars so I'll keep it around. As for the changes I added the HP points into speed and switched Weather Ball for Heat Wave, as Weather Ball is extreme niche and situational on this team.
Mega Charizard and Greninja (Removed)
3 megas is way too many megas, so I removed both of these and replaced them with a different Fire and Dark type...
Incineroar
Even without Knock Off, Incineroar is still an incredible pokemon, and gives you some support which you really needed.
Incineroar @Sitrus Berry
Ability: Intimidate
Points: HP: 32 / Atk: 2 / Sp.Def: 32
Careful Nature
-Fake Out
-Throat Chop
-Parting Shot
-Flare Blitz
Fake Out stops a threat for a turn, Throat Chop deals some damage and can stop Sound moves like Hyper Voice and Parting Shot, Parting Shot weakens a target and let's you pivot to an offensive mon, and Flare Blitz does big damage.
As for the other slot that's still empty, I added another support pokemon...
Whimsicott
Whimsicott is currently the ONLY Prankster pokemon with Tailwind, which is why I chose it for this team.
Whimsicott @Mental Herb
Ability: Prankster
Points: HP: 32 / Def: 2 / Spe: 32
Timid Nature
-Tailwind
-Moonblast
-Encore
-Taunt
Tailwind gives you speed control, Moonblast is your damage source, Encore punishes defensive play, and Taunt stops Status moves.
Palafin
No changes, I was happy with this pokemon.
Kingambit (Removed)
Kingambit was doing well, but I had to remove it for a actual Fairy resist, and this is the one I selected...
Aegislash
Aegislash is very bulky when in Sheild format, and also hits very hard in it Sword form.
Aegislash @Metal Coat
Ability: Stance Change
Points: HP: 32 / Atk: 2 / Sp.Atk: 32
Quiet Nature
-Flash Cannon
-Shadow Ball
-Shadow Sneak
-King's Shield
Flash Cannon and Shadow Ball and STAB moves, Shadow Sneak is priority, and King's Shield keeps Aegislash safe.
Pokepaste: https://pokepast.es/6ec194485324df15