It sounds like you are looking for an understanding of how the HPC efficiency affects the overall engine performance. My suggestion here would be use NASA's excellent engine simulator: https://www.grc.nasa.gov/www/k-12/airplane/ngnsim.html One of the many variables that you can play around with is HPC efficiency. Note that as you decrease HPC efficiency, overall EPR is going to drop. In a real engine, the controller will notice this and dump in more fuel to compensate and get back to the original EPR. In this simulator, you will have to do that by adjusting the throttle controller.
Here's a screenshot of the engine simulator running. The one on the left has a high compressor efficiency and the one on the right has a low compressor efficiency (note how i've changed the throttles and the different fuel flow). Note how the temperatures on the right are all higher. This a symptom of a less efficient component. The engine has to work harder to generate the same thrust. There are a number of other outputs. You can also play around with other components, e.g. see how a degraded turbine efficiency looks versus a degraded compressor efficiency.
The only thing that this simulator does not have is rotor speed. For that, although I've not run out the calculations, I think that fan speed won't change too much with HPC efficiency, at least for a high bypass configuration. Like I said, the control is going to change fuel flow to get back to the same thrust (via EPR), and since the majority of the thrust comes from the fan, the fan speed will be about the same. The core speed, on the other hand, should go up. Because the core has to work harder to produce the same amount of energy output.