Welcome to Nintendo 3DS Community! Glad to see you play Mario Kart 7 and Luigi's Mansion 2, those games are awesome. I'd definitely be willing to play against/with you in either game.
Also, if you're having trouble with either game, there's guides here and on the main Nintendo 3DS Daily site you could use.
Resident Evil Revelations and Tetris are good games too, just not ones I know much about.
I appreciate the guides, I beat Luigi once already but upgraded to a 3DS XL and redownloaded it instead of transferred so my old save file went poof XD. Oh well it's worth a second play through anyway.