Probably never.
Its true since time doesn't pass in the game he will truly never finish making the building and you can talk to him all you want he will still never finish.
The man who is building that building will never ever finish that's because time doesn't pass in the game.
No, but he does in silver and gold.
Trade, Train, Evolve, Catch, Breed all the pokemon!
You cannot 'finish' Pokemon LeafGreen and FireRed. You might be thinking about defeating the Elite Four. That is the end point of most trainers, but you can go ahead and capture legendary Pokemon like Mewtwo, Lugia and so-on.
No but it is essential to trading with other games.
To get Suicune you need to had chosen Charmender for your Starter Pokemon .Then finish the Elite Four .And
You can only get inside when you fight finish the Pokemon league .
you have to trade all of the hoenn-exclusive Pokemon from a Pokemon ruby/sapphire/emerald cartridge
...? umm this question doesnt make sense. you do it by seeing Pokemon! all the Pokemon in the game! (no trade)
You must defeat the elite four and the Pokemon champion then catch all the Pokemon which is only possible with help from friends.
start with bulbasaur an finish the game (includeing n dex) and done
finish the pokedex Dee Dee Dee celebrate! level it up