Any suggestions?
Abomasnow has decent synergy with your team, so it could fit in with Cress, Metagross, and Terrakion.
This team looks pretty solid. The only thing that could possibly be changed is Zapdos's EV spread. You could forgo some attack or speed to invest in a little more bulk. The bulk could help take a few more hits, but if the current spread is already good for you, you don't have to change it at all.
If you're looking to replace Hitmontop, what are you hoping to use in it's place? (i.e. another Fake Out Pokemon or?) I understand your individual choices, but how do all these Pokemon work together? Has your team been handling threats well? We can't really help your team unless we know more about what's working and what's not and what you want this team to do. Not sure why you keep bumping when you only asked about a change once, people will post eventually.
I would run hp grass on him, but then how would I handle abomasnows and ferrothorns. Btw, I have no problems with gastrodons, since latios can take it down easy.Rotom-W is the best one you listed. With Sitrus and protect. Water gem is also an option, grabbing you ohko's.
Though I'd run Hp grass over Hp fire, to deal with Gastro and other Rotom-w.