You can use any 5V usb charger that outputs more than 500 mA. I'd stay away from $2 ebay chargers though.
I bought this charger here. http://www.amazon.com/gp/product/B00K68E6A6/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1
Well that's different. You said 'charger' which means the actual thing that plugs into the wall. The thing you linked to is simply a cable, and personally I would not use one that wasn't MFI certified since it could have a useless lightning chip in it.
yes, i have done research digging deep, and it will if its not certified, my iphone 5 would run hot and die with-in 2-3 hours, so its best to just use the original charger to be safe
I use my HP Touchpad charger because it outputs 2A. I have been using it for 6 months on my iphone 5s and it charges it quickly and the battery life is still great.
Aside from the fact that really cheap chargers can actually damage your phone, there are also two different methods that chargers use to supply a device with more than 500mA of power (500mA is the USB 2.0 default amount). One method is used by Apple, and a different method is used by Android and other devices. An iPhone can charge at a max of 1A, but to get that much power you have to use a USB charger that is set up for at least 1A using the Apple method (otherwise, you will just charge at the default 500mA, which takes about twice as long). That's why some multi-USB chargers will have Apple ports and Android ports.
Hmm, don't know about that. I use a 2A Samsung charger to charge my 4S, and a Cydia app called BatteryLife tells me the phone draws over 900 mA from it.