cave of oragin
in a diving spot
yes
You have to migrate from Sapphire or Emrald.
go to the weather institute guy he will tell you were the weather in strange then go there so I hear
Groudon Kyogre Rayquaza Latias (u can only catch one, either latias or latios) Latios Regice Registeel Regirock
raquaza is at the sky pillar latias and latios will be found randomly kyogre is at the marine cave groudon is in the terra cave mew and deoxys are both at ilands
you can only do this if you have beaten the elite four and have captured kyogre, groudon or raquaza(depending on what game you have.) use rocksmash at the entrance for groudon/ruby surf at the entrance for kyogre/saphire or fly for rayquaza/emrald kyogre will make the water rise, groudon will make land stairs, and rayquaza will make a cloud path. hope this helped :)
YES
you will get kyogre in emerald is to finish the elite 4 (tip to finish elite 4)(catch reyquaza at the sky pillar near pacifilog) you will get reyquaza after when groudon and kyogre fight. after you finish the elite 4 go to thge weather intitute go to the 2nd floor and talk to the man in front on the computer he will say there something stange on one route when he say the route go to that route and you will find kyogre yhe sign if kyogre is there is when you spot raining only in the ocean you will need a hm surf and dive when you use dive you will see a cave before you battle kyogre save the game first to make sure you can battle kyogre again when you lose or when you kill kyogre you can catch groudon to just talk to the weather man again and check a route that is bright then you will see a cave then you will fin groudon save it first (you will need 50 ultra balls each of them.)
Nowhere.
You do not get
No.