As long as the pokemon isn't Version Exclusive such as trying to trade new pokemon into older games. Example: White Kyrem/Black Kyrem trying to trade to Pokemon BW. That is invalid. However trading pokemon like Reshiram into Pokemon BW is valid.
Yes, there are in-game trades in Pokémon Black 2 and Pokémon White 2. There is a trainer in Route 4 that will trade you a Petilil for a Cottonee in Pokémon Black 2 or in White 2, the Trainer will trade you a Cottonee for a Petilil.
There is a Trainer in Route 7 that will trade you his Gigalith for an Emolga.
You can find a Trainer in Humilau City that is looking for a Mantine and will be offering a Tangrowth in exchange for it.
You can also find a Trainer in Route 15 that is looking to trade away her Rotom in exchange for a Ditto.
You will find a Trainer in Accumula Town that will be offering her Ambipom trade, she'll be wanting an Excadrill in exchange for it and after you accept her Ambipom trade, she'll then be offering to trade her Alakazam in exchange for a Hippowdon.
Yes! You can do that.
when you beat the game.
Yes, you can do it. (P.S. I have done it before)
A trade is required from white or white 2 where it can be caught
Rufflet cannot be caught in Pokemon Black 2, you must trade from White 2 or White.
You cannot get it in black 2 or white 2 but you can trade it across
You cannot find Mewtwo in Pokémon Black, White, Black 2 and White 2 so you will have to trade for 1 or you will have to transfer it from a previous game.
You need to trade from white
can you TRADE for a pansear on POKEMON WHITE 2!
according to serebii.net, there is no victini event in black 2 or white 2,so you need to trade from black or white.
In Pokemon White you'd have to trade with someone who got it in Black/White 2
You can't. You'd have to transfer it from a Pokemon Black/White/Black 2/White 2 game or trade for one on the GTS.