In both no.hats.v2017.12.22.fix.vpk and headsfeet.v2017.12.22.fix.vpk the file sd_tattoos_scout.dx90.vtx isn't empty like all the other .vtx files.
In headsfeet.v2017.12.22.fix.vpk:
pyro_rocks_mask.dx80.vtx and pyro_rocks_mask.dx90.vtx are causing an invisible pyro head. (Nose Candy - Horrific Style)
bak_fear_monger_s1.dx80.vtx and bak_fear_monger_s1.dx90.vtx files (one of the two Fear Monger styles) can be added to headsfeet as it doesn't cause an invisible head when removed.
The Triclops and Person in the Iron Mask can also be added to headsfeet as they don't cause invisible heads when removed.
SithreisStill a couple things causing missing feet/heads
for scout
Buck Turner All Stars
The Argyle Ace
Teufort Tooth Kicker (fine on soldier, engy, sniper, but broken on demo too)
pyro
Mair Mask
Hazmat Headcase
Using headsfeet.v2017.12.22.fix.vpk I didn't have any invisible issues with these cosmetics.
Festives:
Also for anyone interested in troubleshooting, I made this vpk here to block the new festivizers in addition to the old blockable festives mentioned here. Unfortunately it doesnt work consistently and I dont know why. I've tried 'preloading' my own festives, merging it with nohats, etc. Which weapons end up having the lights blocked is a crapshoot. :(
I figure there is a chance it could be related to the December 21, 2017 patch note "Fixed a bug that prevented already-Festivized weapons from drawing their lights".