Absolutely! But you have to have beaten the Elite Four. They're level 70, so be prepared!
Yes both can be obtained.
you beat Archie on emerald
You can't get Kyogre in Pokemon Ruby but you can get Kyogre in Pokemon emerald and sapphire and in ruby you only get groudon and rayquaza. In sapphire you get Kyogre and rayquaza and in emerald you can get groudon, Kyogre, and Rayquaza.
groudon,kyogre,rayquaza
Sootopolis City
You don't
There are many legendary Pokemon in emerald, such as groudon, rayquaza, groudon, deoxys, and such. Groudon and Kyogre are not available until after beating Wallace, but Rayquaza can be caught right after the major battle between groudon and kyogre.
In what game? In Ruby, Groudon is n Cave of Origin, before Rayquaza In Sapphire, Kyogre replaces Groudon. In Emerald, Groudon is in Terra Cave and Kyogre, Marine Cave.
No, you need to get Ruby. Or you can get Emerald where you can get both Kyogre and Groudon, including Rayquaza.
sootopolis city
Kyogre,Groudon, raquaza, Latias and (or) Latios
Rayquaza, Kyogre, and Groudon
Yes, you can!