he is the owner of the Pokemon mansion.
he is in the Pokemon mansion
it says nothing
Trophy Garden in Pokemon Mansion on Route 212 [talk to Mr. Backlot after you get the National Pokedex. Mr. Backlot is in the mansion, I think]. Hope this helps! Master
You Have to get a cheat code or that's what i was told
YES.
after defeat elite four
You don't, Mr. Backlot doesn't show you Manaphy but there's a book in his room that will show you a picture of Manaphy as well as add it as a "seen" Pokémon to your Sinnoh Dex.
He is in the Pokemon Mansion on the route below Hearthome City.
You have to have national pokedex.
Get it off a wild pikachu, in mr backlot's garden.
You talk to mr. backlot in the Pokemon mansion south of Hearthome city!
In the Trophy Garden behind Mr. Backlot's house.