See question "Is this a good team to beat the elite four"'s answer.
nothing
When you beat the elite four.
yea so dont use one in the elite four
No, you can just train your Pokemon against wild Pokemon to level up. But it's a little quicker going against the elite 4 cos their Pokemon are higher level than wild Pokemon.
your strongest Pokemon
See question "Is this a good team to beat the elite four"'s answer.
Yes
They are still in the Pokemon league
nothing
level 55 and up and ever type of Pokemon
There is no easy way to beat the Elite Four. You have to level up your Pokemon and use the right types of Pokemon against each of the elite four (i.e. don't use a fire-type Pokemon against water-type. Use electric instead). I recommend level 60 or so for the Elites. Good luck!
weedle, sparrow, geodude, nosapass, skitty
Elite Four Sidney/Sydney: Uses Dark Pokemon Elite Four Phoebe: Uses Ghost Pokemon Elite Four Glacia: Uses Ice Pokemon Elite Four Drake: Uses Dragon Pokemon Champion Steven: Uses mostly Steel & Rock Pokemon.
There aren't specific Pokemon for battles.You should use your strongest Pokemon.
Yes you can
When you beat the elite four.