Shutdown charging is better than boot charging, shutdown charging and boot charging do not affect the use of lithium-ion batteries, lithium-ion batteries are characterized by the best fast charge and release, that is to say, do not wait for the power to run out and then charge. However, it should be noted that do not play games when recharging, so that the mobile phone is obviously more serious fever, and the heat damage to the system CPU is still very great.
No, because it's got overcharge protection
It won't. Today's phones are protected by charging chips. Once it's full, it breaks. It'll be fine if you plug it in and charge it after you turn it off.