Bought the car used, coolant reading is at this level.... Heat blows hot and there doesn't seem to be any issues.

However, I'm planning to do a coolant flush soon, just to keep up with maintenance. Should I also go ahead and replace the thermostat, or is this a normal reading?

 

About normal. Honda's all typically read 1/3 up the gauge for normal operating temperature. The temperature gauge is more of an idiot lamp anyway. That 1/3 location is about 156F to 215F. If you want more detail you will need a scan tool.