Rad Fans - There is nothing wrong with using a coolant target temp for fan control. You can also use a curve based on a temp, or the difference between two temps. I subtract ambient temp from coolant temp and use the difference as the control source for my rad fans curve. This is a pretty common practice since it removes the affect of seasonal changes in ambient temp on fan speeds. You can expand on this in the Playground with logic that says use the difference between coolant and ambient but if the CPU or GPU temps exceed certain values, run the fans at 100% until CPU and GPU temp drop below another certain value. Example - Normally your rad fans speed is determined by coolant/ambient Δt, but if the CPU hits 85°C, fan go to 100% and stay there until CPU temp decreases below 75°C.

Pump - You can vary your pump speed based on a target temp or a curve but it has been shown many times that varying pump speed, outside of extremes, does not really make much, if any difference. I set my pump to 90% of max and just leave it there. I don't start to see temps rise until I slow the pump down to around 40%. I could just run the pump at 100% but I feel like 90% may be a little easier on the pump. Higher pump RPM will result in higher flow rate but this does not affect coolant temp that much, again within a reasonable range.

Note - if you really want to get fancy, and you have temp probes and the inlets and outlets of your rads, you can calculate the amount of heat a rad is dissipating based on inlet temp, outlet temp, flow rate, and the specific heat of water.