Well my team would curbstomp you if it didnt scale down. Level 100 Garchomps have a tendancy to do that.
Based on the levels, i would say you are almost at the league, if not just finished.
This means that you pokemon are most likely not got good IV's or Natures, even if they are EV trained, because noone uses compedetive methods to beat the main storyline.
Since you are using blaziken, i can probably be sure that i wont need to deal with MEga Venusaur.
My charizard is Bloody fast and could probably outspeed your Greninja, then kill it with outrage, or failing that, take a surf and kill it on the next turn. If you swap to Aggron, a brick brak would most likely OHKO/2HKO
Aegislash is a problem. I have yet you find a counter for them that does not include a bigger aegislash, but i'm sure tauning them so they cant set up swords dances or go back to sheild form is usefull, after which i can use something to take the attack and kill with fire.
Noivern isnt a problem, i can speed blitz it with my greninja, which is better than yours because i got lucky on a wonder trade. (Protean, Timid + 31 Speed & Sp attack IV) So i'm sure i can outspeed it and ice beam it.
Like i said, Venusaur goes down to CharizardX, and I could probably beat Blaziken with greninja, if i dont let it get to many speed boosts in.
Oh yea, i still need to give you my team, dont i.
Garchomp
Aegislash(I said the best counter for one of these is a bigger one)
Charizard X
Protean Greninja
HM Slave 1
HM Slave 2