So as far as I can tell it is in fact legal to create a Fireteam Core of 5 Vet Kazaks by combining the above rules. Vet Kazaks can form a Special Fireteam with 3 Vet Kazaks and 2 Frontoviks. However, Vet Kazaks also have Wildcard Trooper, which lets them join ANY fireteam in the TAK sectorial. Now in order for Wildcard Trooper to work at all with any fireteam, they have to be allowed to replace even specific troopers which may be necessary for a Special Fireteam. Which means it is totally legal for someone to form a Special Fireteam Core of 3 Vet Kazaks, and then have 2 more Vet Kazaks use Wildcard Trooper to slot into the Frontovik slots that would normally be the only other valid choices in that Special Fireteam. Is this correct? It certainly seems so.
Or rather they don't have it written in skills & equipment like other troopers, despite the fact that Fireteam: Core is neither a skill, nor equipment. #petpeeve The ever wonderful IJW already has the updated and correct Fireteams list up on the wiki: http://infinitythewiki.com/en/List_of_Fireteams#Tartary_Army_Corp
Rely on Wiki and Profile PDFs for link info. Like picking up the fact that Ikari are allowed Druze Haris, but Army decided to remove the profile :P
Though it is legal to make any combination of Fronto + Vet Kazak Fireteam (except 5 Fronto) because of possibility of replacing the 112 with a Vet. That 3 Vets + 2 Fronto special fireteam is wasted ink.
I wonder why it even exists in the first place? Was the Wildcard added later? Is there some interaction we donĀ“t see (yet)? I mean, they have it written down twice, under Frontos and under Vets, Someone should have caught it.