The WiFi thing sounds like it could be a hardware fault - take it in to the genius bar and they'll fix/replace the machine. Hell, from my experience with Apple support they'd almost replace the machine just because of the shift key if you're polite enough.
When my 2011 MacBook Pro (the one with the faulty graphics card that would eventually die) was in for service, before the replacement program, they called me and said "Oh, we noticed that your trackpad button felt a little weird, so we're replacing it, free of charge". This was on top of replacing the logic board for free as well, even though at that point the replacement program hadn't been announced yet. The next time the graphics chip failed they just ended up replacing the laptop with a brand new 2015 model for free (top of the line model too, which was nice).