Also, can I install Windows IOT on this or is only Zephyr/Linux supported?
The Quark SE C1000 Development Board is supported on Zephyr ... that list appears to not have been updated.
If you look in the boards dir you will see the board support - both the X86 and ARC cores.
x86 Core ... boards/x86
ARC Core.. boards/arc
OS's currently supported are RTOS/Zephyr and QMSI(Baremetal)