Has anyone been able to use a USB UART device to use ICD in Microcode Studio? Or any RS232 device for that matter?
never in a reliable way , ever

apita making a separate model to suit every different osc and config variation for every chip i use .
and after all that effort to be met errors or a stubborn refusal to connect or it only works for a few minutes , then you need to recompile to continue, just junk imo a total waste of time.
xc8 mplabx , wonderful, better than arduino ide for debugging too