Hi! Moved this here since we have an existing thread for team help. First off let me state that PS actually has a ladder for BSS and I would recommend trying that ladder for testing before jumping onto the 3DS ladder, BSS and OU are actually very different so the OU ladder honestly isn't going to be too helpful here. The mention of Ash Greninja tells me you're probably not super familiar with the rules of BSS since it's actually not a legal Pokemon here, so I'd highly suggest reading this short introduction real quick.
As for the team itself, there's not really a ton I can say but most of this team is actually fairly non-standard for the BSS metagame. Zapdos and Landorus-T are fairly solid picks, though Zapdos tends to lean towards physically defensive spreads and wants HP Ice more than HP Grass, and the Landorus-T set you're using is fairly non-standard. I'd recommend Swords Dance instead of Defog if you're sticking with the Z-Fly set though. Defog (and by extension Rapid Spin) is also a worthless move in this meta since the utility of removing hazards is significantly reduced when you can only bring 3 Pokemon to a game. This is made worse by the fact that hazards as a whole are basically not relevant outside of Stealth Rock and occasional Sticky Web, with the latter being only used on very specific team setups.
The rest of the team tends towards the lower end of the spectrum in terms of viable threats though. Outside of possibly Magnezone, you could probably replace just the rest of the team to make it more meta relevant. However, rather than give major team change suggestions, there's a few set improvements that can be made if you'd rather stick with some of these. Mega Latios is basically not a relevant Mega whatsoever in BSS though, but if you're sticking with it I would suggest Shadow Ball over Energy Ball so that you can hit Aegislash. Realistically you're better off using Calm Mind Mega Latias here though, or Dragon Dance Mega Salamence if you want a physical Dragon-type. Terrakion is not that bad, though I would suggest a Focus Sash set with Rock Tomb over Stone Edge and Earthquake over Iron Head. This makes it a fairly reliable SR setter with a useful speed control option that can push speed tiers in your favor. Furthermore I'd switch Magnezone to an Electrium Z or Assault Vest set here and use Sturdy or Analytic instead of Magnet Pull, with Volt Switch over Explosion. Hidden Power Water is iffy over HP Ice though it's workable, whatever works for you. Lastly, I think Clefable is bad in this meta but some people still find it to be an acceptable pick with a Calm Mind set using Moonlight and Stored Power. Wish and Heal Bell are usually not good moves in this meta since switching tends to be more difficult and the utility is significantly reduced when you aren't bringing your whole team.
Hope this helps you out, and if you have more questions extending beyond this thread I'd suggest checking out the Battle Spot room on Showdown or the Battle Spot Discord, both linked in this thread.
