You can't. It is only in Pokemon Black. You'll need the Action Replay or wait for another event containing it.
No, not in the wild.
you cant unless you use A R codes if you look at all the vids on how to catch reshiram in white every one says while entering the battle a wild reshiram apeared.
Yes, but not by wild. You can trade for another Reshiram from someone.
You cant't obtain it in the wild the only way to get it is by trading
For wild, catchable ones, it is Cottonee, Gothita and Vullaby. Cottonee however can be traded from an NPC in Nacrene City. Then as well as these, the legendary Pokemon Tornadus and Reshiram are Black-exclusive.
Zekrom cannot be found on a mountain nor can it be shiny. Nintendo made this because meeting Zekrom or Reshiram is not considered a "Wild Encounter". Zekrom can be found in N's Castle only.
it depends wheather you like Zekrom or Reshiram. To me i would get white whcih has Zekrom
No where
It lures wild Pokemon.
You cannot catch a wild eevee in black or white
Due to White Forest, White has more wild Pokemon than black
as far as i know its not possible to obtain a "wild" groudon on Pokemon platinum. however you can trade it in from other games such as Pokemon soul silver.