W1700K2 is compatible with 6.3x3mm plug.
OEM Bootlog (too long to post here)
Yes. It uses RTL8261CE. The kernel module is shipped within the stock image, but there is no source for dkms or such. There is no support for RTL8261CE in the Linux mainline.
Also, it is already shipped with WXK002-05.03.41.02.bin, so I guess this is the latest?
EDIT: The fan controller is Nuvoton NCT7802Y.
EDIT2: I see NCT7802Y has upstream driver in Linux mainline. Can you include this in the build (and would it be enough to support this?) ?
EDIT3:
The AN7581 version is E2 and it is confirmed by:
ECNT> md.l 0x1fb0005c 1
fb0005c: 00000002 ....