Based on past sales and similar product like skylanders and infinity which sales add-on toys to be used with E rated games. 

Nintendo on the other hand is advertising the Amiibo for multiple games of which the target audience is a more mature audience.

Super Smash Bros - wiiu & Hyrule Warriors - Teen rating

MArio KArt 8 - Captain Toad - MArio Party 10 (eventualy) - E rating.

Amiibo's I would say are actually targetting Nintendo Fan of all age and not directly toward the younger crowd.

All I got to say is Captain Toad Amiibo better be package with Captain Toad- Treasure Tracker.

PS. I have already pre-order Zelda, Samus, Villager, Marth (why don't they have Ike??????) 

Also, Will you be opening your Amiibo's??? I am tempted to just keep them just has a great collectable items.

I think its mainly kids with a sprinkle of mature fans

Starting out, they're definitely going for the all-around big Nintendo fan regardless of age. Smart move.

But by the very nature of being a toy figure, Amiibo naturally appeals to a much younger audience -- an audience Nintendo has had more trouble getting engaged with their brand over the last few years.

So ultimately, it's a strategy to win children away from Skylanders, away from the iPad, away from another console, away from pretty much any other form of children's entertainment.

people with too much money.

Super Smash bros Melee & Brawl were Teen rating! 

Just checked Super Smash Bros Wii U get E 10+ rating.

Nintendo fans. Just like all the other games and stuff for the WiiU they are releasing now. They have given up on the casual market when it comes to the console, thank god...

Kids and hardcore Nintendo fans and collectors.

Depends really.
Main audience are probably kids, but some nintendo fans and collectors will buy a few of them.

The target is kids, plain and simple. Just like with Infinity and Skylanders. The inherent appeal however is a little broader, because Nintendo is famous for its kid properties/games that appeal to everyone, whereas I don't feel like quite as many adults would want to play something like Skylanders in particular, which is probably a bit too basic for anyone but kids.