Ferrothorn is certainly a good option for Team 1, it is the first thing I thought of as well. Dragonite isn't exactly a threatening Pokémon that needs to be checked, and Ferrothorn has Iron Barbs which is great for punishing U-turn from Greninja. It's also a solid switchin to Dragonite. It has some flaws though; Ferrothorn has even worse offensive presence than Dragonite, for example Team 2 can respond with something like Breloom. This would be terrible for Team 1, Breloom can switch in on Ferrothorn pretty much all the time and Spore is very crippling (you can try to absorb the sleep with Ferrothorn but then it will just Drain Punch you). Also, picking a Stealth Rock user that early, imo, means that it needs to be one with notable offensive presence. Ferrothorn isn't exactly something that can reliably keep Stealth Rock on the field really, since Team 2 can respond with the proper hazard remover, for example bulky Rapid Spin Excadrill means that if Team 1 wants to keep Stealth Rock up they also need it to pair it with a spinblocker that isn't Aegislash or Gengar, so you're pretty much left being forced to use something like Jellicent. That, or just give up on having Stealth Rock on the field all the time, which really is too bad since that's how Landorus can probably break though Team 2.
It's still a cool pick though, it will pull its weight and right now it gives Team 1 an advantage over Team 2, but I think it might be too easily abusable by Team 2 as well.