Jolteon's moveset is ok, you may want to replace either Agility or Double Team with Thunder Wave.
Ho-oh's set is standard.
Meganium's moveset is fine. Keep Razor Leaf on Meganium, don't replace it with Solarbeam. Sunny Day's effect lasts for 5 turrns after it is used, and I don't recommend bringing in a fire weak Pokémon like Meganium while Sunny Day is in effect. Even though Sunny Day has some good effects on Meganium, like allowing it to use Solarbeam without charging, and getting full recovery from Synthesis, the downside of Sunny Day isn't worth it. Sunny Day makes fire type attacks 50% stronger, and if Meganium were to get hit by a Sunny Day powered Fire attack, when it is already weak to fire, the results won't be good. So just keep your moveset as it is, although Leech Seed could be a decent option over AncientPower.
Blastoise is ok, just go with Rest over Attract. Haze over Earthquake also wouldn't be a bad idea.
Crobat's set is good.
Golem-Very good, I still prefer Leftovers as an attachment, but Pink Bow will work to boost Explosion's power, so whichever attachment you prefer will work.
Overall: Your team has a 3x Ice weakness, (Meganium, Crobat, and Golem.) and a 3x Electric weakness (Ho-oh, Blastoise, Crobat.) Also, your team will have a lot of trouble dealing with a Pokémon that has Earthquake and Rock Slide, such as Machamp or Tyranitar. Considering how common Electric and Ice attacks are, you may want to consider changing a couple of the Pokémon in your team so that you are not so weak to those common attack types.