There's some other things I wanna know.
- No matter how high level your party is, is the Gym leaders always 1 or 2 levels ahead of you?
As had been mentioned several times, this is not, nor has ever been the case. If you've been following my progress, one thing you'd note was that I had a MASSIVE level advantage. My team was easily twenty levels ahead of the gym leaders. Twenty levels ahead of the Elite Four and Champion by the time I got to them.
The secret? Grind like hell. The level cap each badge is an invitation to grind and grind and grind.
- What is the purpose of your Pokemon Amie decorations you can add in that empty area? Is it just for show, like in a house, or does it actually change stats or something? What about adding the Poke Puffs in the room?
You can place cushions and chairs in the middle of the room where other Pokemon congregate. I have three chairs and a table there. When you place objects like that, the screen will show a white dot where you can put them.
You can drop a Puff into the room and visiting Pokemon will eat it. Sometimes, they'll leave you slightly better gifts.
- How long does it take people to complete through the game, and get to elite four in this game? Last I seen Vixy stream through that one weekend she was already half way, and beat it within that same weekend she streamed. But it looks to me that all pokemon games have been really long.
Depends on the player. Some people took a few days. I took a few weeks, as I spent most of it grinding and earning money to buy stuff. It's up to you how long you want to take.