To answer your questions:
1. On my bedroom unit, which is seldom used, I use a USB powered laptop drive in a caddy, with USB power from HB-1000S. So only powered up when the Humax is.
See also the FAQs https://myhumax.org/forum/topic/hb-1000s-is-this-unit-pvr-ready.
2. I do not know the Foxsat HD only the HDR. The HB-1000S and HDR units have the same firmware. Sensitivity and selectivity and difficult to know exactly what you mean but I imagine the answer is yes.
3. Yes, change to non-freesay mode. You can then see all the channels numbered from 5000 – it is difficult to identify the channel other than by watching it and creating a written list of what is what.