I believe that Entei, Raikou and Suicune appear only in Kanto but I am not sure. as for Shiny pokemon... No matter how you attempt to get a shiny, SRing, eggs and wild encounters the chances will ALWAYS be 1 in 8192. The shiny chances are like flipping a coin (only its not 50-50) if you flip a coin and get a tails will you be garanteed a heads next time you flip? No you will still have those same chances of the coin landing on heads or tails 50-50. So even If you battle 8192 pokemon you are not garenteed a shiny. even ask Alzi~Pokemon_Master he has SRed over 100,000 times and still hasn't encountered shiny Rayquaza.