No you cant catch Latios in Pokemon Colosseum. You can only trade it in from your Ruby or Sapphire game in to the Colosseum game and that's the only way you can get it.
no
Latios cannot be caught in Pokemon Diamond. You must get one off the GTS if it is in your Pokedex, or you must migrate it from Pokemon Ruby, Pokemon Sapphire, or Pokemon Emerald.
The final Colosseum is the Deep Colosseum after the Game, Pokemon here are Level 60-65, this is where you can catch the Pokemon you missed from the Admins earlier and a Shadow Shuckle.
you cant dummy
You can't. You have to trade it from Colosseum.
Transfer from GBA via palpark
No you will need Emerald or Pokemon Colosseum to trade you a Sudowoodo.
No, mismagius was not created in the time of that game. You can catch a misdreavus though.
catch celebi
Its not possible to catch Ho-oh in emerald to get one receive one from Pokemon colosseum.
You can only get celebi in Pokemon XD by trading. The only way I know you can get a celebi to Pokemon XD except from events is the Pokemon Colosseum Bonus Disc.
You cannot catch a Stantler in Firered get one from Pokemon emerald or Pokemon colosseum.