Kyurem 2: it doesn't have IV 31 in Atk if the characteristic is "Proud of its power". Unlikely to be hacked. Seems like a random shiny.
Kyogre: again, it can't have IV 31 in Sp. Atk if the characterstic is "Often lost in thought". Depending on the actual IV spread, it can be hacked or not.
Rayquaza: if it does have IV 31 all, then definitely hacked, as Rash IV 31 all spread does not exist in RSE, emulator RNG or not.