Resistor Load Effect on inverting op-amp
For calculating the voltage and current of R3 (of the second circuit) you could say that it is virtually in parellel with R2. But that is where the similarity ends.

A major part of analyzing an op-amp circuit is to use the feedback current flowing to (or from) the -input pin position to determine the circuit operation.  In this negative amplifier configuration the feedback current is equal and opposite of the input current, this keeps the -input pin at a virtual ground (equal to the +input pin).

In the second circuit, the load resistor is "shorted" to the actual ground, so the current through that resistor does not affect the feedback section at all. 

In the first circuit R2 being shorted to ground does affect the feedback current. 

So your progression from the first circuit, to the second, then the third does not follow the correct idea in terms of the feedback current, so each circuit will operate differently.