I think your best bet is to record the kemper analog into channel 1 and 2 of your twin.
Don't think so. This way add an additional latency cause of digital-analog-digital convertions.
The best way to connect your Kemper into Twin X is to use Kemper's S/PDIF coaxial out. You have to install coaxial-optical S/PDIF convertor cause Twin X doesn't have coaxial S/PDIF in, just optical.