An attempt at deep West Eurasian phylogeny

[Kale]

Gravettians have 0 WHG as far as I am concerned, WHG have Gravettian ancestry. Why? Because Anatolians and Kotias UP do not significantly prefer Gravettians over any UP Europeans

Chimp.REF Italy_Mesolithic.SG Russia_Kostenki14 Czech_Vestonice16 0.00434 0.000710  6.12 9.41e-10 692648
Chimp.REF Georgia_Kotias_UP Russia_Kostenki14 Czech_Vestonice16 0.000786 0.000811 0.969 0.333 399666
Chimp.REF Italy_Mesolithic.SG Bulgaria_BachoKiro_MiddlePaleolithic Czech_Vestonice16 0.00185 0.000747  2.47 0.0134 670162
Chimp.REF Georgia_Kotias_UP Bulgaria_BachoKiro_MiddlePaleolithic Czech_Vestonice16 0.000334 0.000837 0.398 0.690 386665

I can replicate what you get there... 
Chimp.REF      Kotias_UP.SG Kostenki14 Vestonice16 0.000640503 0.000807950 0.792751 0.427923 401247
Mbuti.DG Kotias_UP.SG Kostenki14 Vestonice16 0.00101933  0.000693215 1.47044  0.141442 417438

But when you group all of the Vestonice samples together with KremsWA (who they share a lot of drift with). Also holding true for Italian Gravettians. Maybe Vestonice16 is just the odd one out?
Chimp.REF Kotias_UP.SG Kostenki14 Gravettian_KremsVestonice 0.00152897 0.000621613 2.45968 0.0139061  560017
Chimp.REF Kotias_UP.SG Kostenki14 Gravettian_Italy          0.00229368 0.000772325 2.96983 0.00297962 424646
Mbuti.DG Kotias_UP.SG Kostenki14 Gravettian_KremsVestonice 0.00145060 0.000547835 2.64789 0.00809971 583059
Mbuti.DG Kotias_UP.SG Kostenki14 Gravettian_Italy          0.00191178 0.000680324 2.81010 0.00495266 442281

There's also of course Muierii
Mbuti.DG Kotias_UP.SG Kostenki14 Muierii1 0.00193502 0.000641769 3.01513 0.00256870 630797
Mbuti.DG Kotias_UP.SG Kostenki14 Sunghir.SG 0.000529895 0.000538229 0.984517 0.324862 631154
Mbuti.DG Kotias_UP.SG Kostenki14 BachoKiro_BK1653 0.000623578 0.000685833 0.909227 0.363230 570252
Mbuti.DG Kotias_UP.SG Kostenki14 GoyetQ116_1 -0.000126294 0.000708969 -0.178137 0.858615 435197
Mbuti.DG Kotias_UP.SG Kostenki14 Gravettian_France_Fournol 0.000908011 0.000755310 1.20217 0.229298 331612

That doesn't necessarily negate your point though, consensus is that Goyet/Fournol have some ancestry that could pull them away from Kotias, maybe Kostenki/Sunghir have some too.