Hello there :) I hope I can provide you with the answers you are looking for;
Concerning trading Pokemon from previous games, it is possible to trade Pokemon either directly with X and Y, use the Wonder Trade feature or GTS (global trade station). Now, I'm not sure if you are aware of this, so I will clarify: with generation 6 (Pokemon XY and ORAS), it is now possible to find (almost) any desired Pokemon on the GTS. People from all over the world can put up Pokemon here for trade, you can find a specific Pokemon you are looking for, and when you meet the requirements the other person would like in return, you can trade. So thats one thing to get the Pokemon you like.
Second, you can also use the Wonder Trade feature; it's trading a Pokemon with another person somewhere in the world, but you will never know what you will get in return though. You can get any Pokemon via Wonder Trade though, its a long shot but nice to try out.
So I would recommed the GTS, since that is the fastest way to look for a specific Pokemon you want. Sometimes people also put shiny Pokemon up there for trade, but often ask ridiculous things in return (like event legendaries, which arent possible to trade over the GTS). But if you're lucky, you can get shiny Pokemon through trade here as well. :)
Breeding, is really useful in the games and often used by a lot of people to get a specific Pokemon they want with certain moves, abilities and stats. You can breed with either two of your own Pokemon (as long one is male and the other is female, or when using ditto you can pick a male/female pokemon along with it). You can also breed with one of your own Pokemon and another Pokemon you got in a trade is its from the opposite gender, or just use two Pokemon with different genders from someone else. Anyway, you can leave these two 'parent' Pokemon with the Daycare (in ORAS that would be Route 117), and after a while there will be an egg for you to hatch :)
Some advantages of breeding are the following:
* You can breed for lets say, a specific ability and nature (like static on Electrike with Timid nature, and you want the hatchling to have this ability and nature too).
* You can also breed Pokemon to 'inherit' the best stats from the parent, so that the hatchling has nice stats to battle competitively (used in stratety battles against others online) - for example, you want a pokemon hatchling with nice speed and HP, so you try to breed with parents with high speed/HP stats so the hatchling will eventually 'inherit' these stats.
* You can also breed Pokemon with special moves they would never learn themselves. This often involes different species of Pokemon to breed with each other, lets say breeding a Mudkip (female) with a Spheal (male) can result in a Mudkip hatchling that knows Ice Ball. Please note that when breeding with different species of Pokemon, the hatchling will always be the same species of Pokemon as the female parent (so in this example, the hatchling will always be Mudkip since the female parent Pokemon here is Mudkip). Also, of course the male Spheal in this matter should know Ice Ball as a move while breeding in order for the hatchling to know this move. This is also a really useful aspect in breeding.
* Last but not least, breeding can also be used to increase hatching a shiny Pokemon. This can be done the best through the Masuda Method. This involves breeding a foreign Pokemon (i.e. a Japanese Pokemon) with one of your own Pokemon (- a Pokemon is considered 'foreign' when it comes from another language-cartridge than your own). Breeding with a foreign Pokemon increases the odds of hatching a shiny. I use this method very often, and it has proven to me it really works. :)
Breeding is a serious matter, so I recommend you should try to find a Breeding Guide (I think it is on the forum as well) to teach you all about it! ;)
I hope you'll understand at least something more about all this, of course if you have more questions feel free to ask (you can also send a message or something) :)
