No,but when Explorers of Sky comes out you can.
No, Riolu was only made playable in Explorers of the Sky.
You can't! You can only get Riolu in Explorers of the Sky.
yes
Wonder mail
yes. yes u can
Celebii, Combee, Pachirisu, Riolu, and Lucario.
From What I know I believe you can only get it as a partner or your main character in Pokemon Sky dungeon.
No there is not.
No. You can get one in Pokemon Mystery Dungeon: Explorers of Time after you recruit Riolu.
Riolu, Phanpy or vulpix
Riolu can be found in Crystal cave and its actually easy to find riolu, but it will take forever trying to recruit it
You can evolve Riolu with the Sun Ribbon.