I'd be willing to pay for DLC for these games, under a condition of course: I don't have to buy it more than once to use it with both versions (in the case it's something like a special cave to unlock a past Legend)
nope, because then if one person buys it and transfers it to the second version for free, then anyone can transfer theirs from the one who bought it for free as well and it will defeat the whole purpose of buying it online. I say if DLC is featured, it will cost for each version, no more mixing records or trading keys via IR.
But you'll probably have to have an SD card with the DLC in it to work. And if the DLC happens to be an added area, then you can't save in it. Pokemon already do this in several areas and in some other games, like Mario Golf 64, you can't save at all if you are using a GBC character.
It'd be sort of like how the PS3 works:
Player 1 buy game X on PSN.
Player 1's GF (Let's call her player 2) has access to that game.
Now Player 1 and 2 break up, and player 1 leaves with his PS3, and start to live with player 3. Player 3 sets up her account on the PS3 and now can access to game X
Player 2 buys a new PS3 for herself. She no longer has access to game X (unless she either buys it or someone set up his/her account with this game available)
It could easily work that way with the possible Pokemon DLC --- Pokemon X/Y are going to blow my mind. They already are. Official Roserade of the Pokemon X/Y boards