Can't say for sure about your first point, but you don't need to be concerned about the second one.
The I/O device is only used for output, all calculations will still use the GPU cores.
One suggestion regarding RAM (if you didn't order yet): please check that you have at least 1.5 GB RAM per GPU core, better 2. For complex operations, like decoding 8K Canon RAW (for example), plus NR, Speed Warp, Enhanced Super scale etc. the computer will use most of that. If the RAM doesn't suffice, it'll still work, but silently swap to the internal SSD. That will not only make things much slower, but ruin the SSD in the long run. Rather save on internal SSD than on RAM. You'll never have enough storage when working with video anyway
