If I understand correctly the polling rate on USB-midi communication is usually 1 kHz.

If a USB-midi device is sending CC-data over USB, let's say a knob is turned swiftly, quicker then the polling rate, then will all CC:s in the same poll be considered arriving at the same time in the USB-host (usually a computer), or are they timestamped so their relative positions are kept, or are all but the last CC per poll conisdered relevant?

Multiple CC messages at the same instant seems pointless in almost all situations as opposed to simultaneous Note-Ons which makes sense. But how is this handled by the protocols?

The question can be reversed. If a DAW has higher timing resolution than the poll rate (Logic as an example has twice the resolution @120 bpm) how is this timing handled when sent out to a USB midi-device?