Xeon W-3175X is 28 cores (and 250W)..

But yes, I would expect a dual die 64 core monster like the 92xx series they recently announced. Of course the 300W power/thermal solution apple was talking about seems a bit limiting in that case.

Yes, but Apple lists 12, 16, and 24 core Xeon W options, none of which are currently available from Intel but do match those leaked for Cascade Lake Xeon W. So it’s quite doubtful Apple is using Skylake Xeon W since the majority of the specs don’t match.