pikachu or a legendary Pokemon
for your party, you'll need Pokemon that know most of the HMs as they are used often
It's possible.If you cheated (used a GameShark or ActionReplay) to obtain certain Pokemon, you COULD encounter glitches.Like, I think that there is a GameShark code to modify a Pokemon in a certain slot in your party into a certain Pokemon. If you tried to trade it, a lot of issues might occur.But if you used a code to encounter a certain Pokemon, you SHOULD be fine.And if it's just a WiFi battle, you should be cool.
Sacred ash can be used to revive all fainted Pokemon in your party.
You should used bug, ghost, and dark type pokemon.
ARCEUS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Go to the Battle Tower then the people should move
Complete burn it will burn up any berry used by a Pokemon
An aggron probably... I used an aggron to beat the elite 4...
You have to have the Pokemon you want to use it on in your party. Then, just go to the Bag, find the Fire Stone and select Use. You will be taken to the Party screen and if the Stone can be used on a Pokemon it will show the sprite and its HP. Select the Pokemon to be evolved and it will evolve. This is the same for all Stones. Hope this helps! :D
You should use either Groudon or your Starter Pokemon. I used a crobat and a garados.
grass types
It depends if it's used on eBay or all new.