Charlie,
I am not an Icom expert, but there is no reason why it shouldn't work if you follow a couple of
steps. The radio type will have to be changed in the RRC's to program mode-1 (CI-V).
The strapping only changes the microphone wiring and has nothing to do with the connection.
In looking at the manual, it appears that the strapping recommendation for CI-V is only to allow
you to use the microphone's "UP" button to make the SIP connection, but this connection can also
be made manually using the control RRC's web interface. Therefore, you can leave the strappings
as-is if this is ok and then the existing microphone will works as before.
If you haven't already, I suggest that you first get HRD to work over the existing setup, then it should
fine once you change it.
Also, I know it is a bit pricey, but the control head is available separately:
https://www.hamradio.com/detail.cfm?pid=H0-01531173,
Mitch DJ0QN / K7DX