Yes it is possible.
You haven't made it far then. You can catch old pokemon. Yes, you can catch Riolu in the challenger's cave after you beat the elite 4. He's rare though.
Catch a Riolu and evolve Riolu.
snivy riolu growlithe tranpinch ducklet evee
yes u can get riolu in Pokemon heart gold and soul silver you catch him or her in the safari zone and you can catch lucario in the safari zone two.
you can't- you have to catch pikachu and evolve him
I think that the season is any season, and you catch him in the Challenger's Cave on Route 9. Also, Riolu is a Pokemon that evolves by friendliness so give the soothe bell and level him up and DON'T LOSE!! That makes a Pokemon less friendly.
riolu evolves when he is really happy
Anywhere that you can catch Riolu. Shiny Pokemon can appear anywhere and anytime; with a 1/8192 chance of one appearing.
You cannot do that unless you have Pokemon rangers 2. So if you want another riolu you have to get Pokemon rangers 2.
No. Riolu did not exist during Generation III, which was the generation Pokemon FireRed & LeafGreen versions were set in.
You Cannot catch lucario on pokemon black the only Way is to trade him or catch a riolu.
You can catch Riolu in Challangers cave. You can't enter challangers cave till you have beaten the eliet four at least once.