After reading the suggestions and your overview of the team, I found some ideas for upgrading the roster.
Starmie: The use of Starmie instead of Gastrodon allows coverage for your switch ins against SR and Spikes, I find this to be a wonderful addition.
Gliscor: The use of Facade I think is helping a bit, the issue I have with the standard Stall Gliscor is that Gengar and steel types just kind of wall them off. (Sat in a GTS battle for a whole hour on a stalemate between Skarmory and my Gliscor)
Replacement for Gallade: After testing a lot of Physical sweepers/stall breakerss (Conk, Gyrados, Gallade, Scrafty & Hitmontop), with your setup, I discovered that a Dry Skin Toxicroak is BEAST with this comp.
Toxicroak (The Boss)
Trait: Dry Skin
Evs:252 Atk / 4 hp/def / 252 Speed
Essentially how this works with your comp, is it encompasses both Gastrodon and Gallade's responsibilities. It Hydration tanks, regains health when switched it on water attacks. I usually use him as a Lead if I see a Politoed on their team or alot of Psychic/Dark. If they switch in a Ninetails, just switch in your T-Tar next turn to knock out the Sunny Day. HE IS SO GOOD <3
(Edit: I did make a proxy of the team and added the additions for about 8 hours yesterday on Sim as research)