Arceus, Victini, Reshiram and Zekrom are all definitely hacked if they are all Shiny. Reshiram and Zekrom are coded not to be Shiny in Pokémon Black, White, Black 2 and White 2 and there have been no Shiny Reshiram or Shiny Zekrom events. Victini is coded not to be Shiny in Pokémon Black and White and there have also been no Shiny Victini events. There have also been no Shiny Arceus events.
Sources: Shiny Pokémon - Serebii, Arceus - Bulbapedia, Victini - Bulbapedia, Reshiram - Bulbapedia, Zekrom - Bulbapedia
Archeops is hacked because the Nintendo DS family does not let you set the date as 00/00/2011.
Kyurem, Landorus, Thundurus and Tornadus at the moment are legit because they can actually be Shiny without hacking so you will have to include more information before I can determine whether or not they are hacked.
Hope I helped :)