Whooops, looks like I've messed up with the terms.
2. Is it possible to pass DW-moves via breeding? I think I've got it this time.
1. I wasn't talking about Wifi. Of course, Roost-Skarmory from the last generation is perfectly legit, but invalid in flat battles, the competitive form of battles these days, right or not.
Going into a little bit more detail than MoltenKyurem:
2. They can be passed only if they are level-up moves for the baby, tm's the baby can learn, or breeding moves.
1. No, you are not correct. As Skarmory can legally know Roost provided it was taught the move last gen or was caught in the Dreamworld (though, in the latter case, it would have the less than optimal ability Weak Armor). The only reason such a Skarmory would be illegal would be...
a.) if it knew a new breeding move from gen 5, however Skarmory got no new breeding moves this gen that it couldn't learn somehow in a previous gen.
b.) if it knew either of its dreamworld exclusive moves (drill peck or roost) along with any move it can only learn through breeding and had its dreamworld ability Weak Armor.