It's tied with A Link Between Worlds as my favorite 3DS game. It was so much fun and had a lot of gameplay for a 3DS game. I think I got about 40+ hours on my first play through. That game is a must-buy for 3DS.
I REALLY liked Kirby 64: The Crystal Shards. The ability to combine different powers was so much fun that I replayed the game a lot. I had so much fun playing that game. Talking about it has made me kind of want to play it again haha.
Hearthstone since you can only use a handful of expressions instead of trash talking. Sometimes people will spam the emotes but you can turn them off easily. The best community that allows actual talking might be either TF2 or WoW.
The simple answer is no. I do all my reading on my Nook so that would still count as a screen even though I'm doing something mentally stimulating. It does look like a real page and doesn't have a backlight though so I guess it is a page/screen hybrid.
I would pick Binding of Isaac Rebirth since it's different every run. I would get a lot of game play out of that before I got bored. I would also pick Minecraft for the same reason. If I'm bored on a desert island I could always find something new to do in that game. Finally I would pick Skyrim...