Okay, in depth check using ntlite to compare infs against LTSC image, it seems 6951 has all the HD5XX, HD6XX and UHD6XX lineup. The 7263 driver only has 510/530/610/630 models despite being larger than the previous driver.
Since most consumer models have HD-X20 series, this seems intentional inf hackery and easily solvable, if only needing some driver signature to install.
Also, tried to find installers to Intel Graphics Control Panel, but unlike Realtek and Thunderbolt, those are online-only installers (what's even the purpose of such packages I'll never know, but.