I think you hit a limitation in Sequel,
I use a different software (Guitar FX Box) and I can set different setting for input/output,
For example I can set Input from CI1 and output to sound card (which seems like what you’re looking for), it doesn’t have to be both Input/Output with CI1, which is what seems to bother you. I suggest you look at how to do this with Sequel or try a different software.