Scenarios where Inductor back EMF would result in damage of circuit or component
As far as your many questions, 

#1&amp;2 are correct. 

#3 may or may not be true. 

#4 I'm not sure what you are trying to say, but the current after the switch opens will ideally be the same as before it was opened. That's a paradox with an ideal switch and an ideal L-R circuit (voltage would have go to infinity to maintain the current through an open switch), but real circuits are not ideal. 

It may help if you visualize a high value resistor, a capacitor or a spark gap across the switch. In a real situation something will limit the voltage, either the switch or wiring will break down, there will be some resistance or capacitance that will limit the voltage. In the case of capacitance it will cause ringing. 

#5 This is not necessarily true. The energy (previously stored in the inductance) can cause damage even if the current would not be an issue. For example when a mechanical switch opens, the resulting high voltage at near the previous current causes arcing and erodes the contacts. Of course the energy is \$L\cdot I_0^2/2\$ where \$I_0\$ is the current flowing just prior to the switch being opened. 

Since usually the switch is a semiconductor in modern circuits, much of the energy will be absorbed by the semiconductor. Some may be absorbed by external resistances (for example, a relay coil with a flyback diode across it depends mostly on the coil resistance to absorb the energy). 

So usually something across the switch is what is called for in order to limit the voltage and mitigate any issues. An R-C snubber, a Metal-Oxide Varistor, a gas discharge tube, a Zener, a reverse-biased diode, a semiconductor designed to avalanche, an active clamp etc. etc.