The S6000SW subwoofer should be compatible with the Denon receiver, as the receiver has two line-level subwoofer outputs that should work with most subwoofers. However, there is no specific information about compatibility with this particular subwoofer model. It is advisable to check the technical specifications of the subwoofer to ensure that it is compatible with the outputs of the receiver.

The two subwoofer outputs of the Denon AVR-X1700H are designed to connect two separate subwoofers. Both subwoofer outputs emit the same signal, which makes it possible to use two active subwoofers for bass support.

With ARC and eARC, one channel of the HDMI output is used to send back the audio signal (e.g. Dolby Atmos), so there is no separate input for this. As far as I know, you need at least an HDMI 2.1 cable for eARC (if it says "High Speed HDMI", that's what it is).

Yes, the measurement microphone is included. The Denon AVR-X1700H comes with the Audyssey MultEQ XT room acoustic measurement system, which includes a microphone to analyse the acoustics of the room and optimise the audio settings.