no
Mt. Coronet is in Pokemon Diamond, Pearl and Platinum, not Ruby, Sapphire and Emerald. You must be thinking about Mt. Pyre.
you beat them
Mt chimney is not on Pokemon diamond, pearl, or platinum. On D&PP it is mt coronet, mt chimney is on ruby, Sapphire and emerald.
Spear Pillar, which is at the very top of Mt. Coronet.
there is no mt. coronet in emerald that i know of
This location is only in the 4th generation Pokemon games like diamond and pearl.
the only way to make magneton evolve is to level it up at Mt. Coronet
In Pokémon: Diamond Version, Pokémon: Pearl Version, and Pokémon: Platinum Version, Loudred can only be found at the top of Mt. Coronet, and only through the use of the Pokéradar. As such, it cannot be obtained until after the National Dex is obtained.
at the top of mt coronet(arch=spear pillar)
Mt. Coronet cannot be reached in Pokémon Emerald. It is not possible to visit regions outside of the version's main setting. It's especially impossible to visit locations or regions that haven't been created prior to a version's release.
You can get clefairy in 2 ways: 1. First you need a ditto and a cleffable. Then you put them at the day care. After a while of walking around, there will be an egg. When it hatches it will be a cleffa. You can level it up until it is a clefairy. 2. You can trade clefairy from Fire Red or Leaf Green onto emerald.
There is a map of Mt. Coronet in the Sinnoh region.