Oh boy, this is gonna be an interesting thread. I'll just answer the second one. If you like RPGS, can't go wrong with Bravely Default or Bravely Second, Dragon Quest VII and Dragon Quest VIII, the Pokemon games, Mario and Luigi Dream Team, Paper Mario Sticker Star isn't for everyone but I think it's fine, Tales of the Abyss 3D, etc.
You can't really go wrong with platformers from NIntendo's 1st party. Kirby Triple Deluxe and Planet Robobot are great titles. If you like Zelda I highly recommend A Link Between Worlds. Kid Icarus Uprising is also an experience I wouldn't miss.
Basically, if it's Nintendo 1st party, have at it. With a few exceptions most of their games are high quality for the device. Mario 3D Land can become highly addictive, Mario Kart 7 is also a good one.
Eh, in terms of hacking it, if you must...Sky3DS is the easiest way to do so. It's not really hacking though. But as the 3DS is still being supported and games are still being sold, I don't recommend it. Especially if you're trying to go online with it as Nintendo will ban you and possibly render your console useless online.