Almost no. It is VERY hard to get a Shiny Pokemon besides the Red Gyarados. (Learned from experience, and the internet) Chances are unchanged, 1/8192 I believe, tell me otherwise and I will edit. I actually have a few. So Basically most unlikely. 1/2048 Masuda method (In only Gen 4? Really? Didn't know that)
Possibly. You have a 1/8192 chance of it unless you use the Masuda Method, which takes the chance to 1/2048 in Gen4.
Basically: Most Likely not.
More on the Masuda Method: http://bulbapedia.bulbagarden.net/wiki/Masuda_method
No, Breeding a shinny Pokemon will not always lead to a shinny Pokemon, though it is possible to get a shinny Pokemon from breeding it is very very unlikely