So I had a big pause in gaming and recently discovered that Tretiak Spec-Ops isn't a valuable in Army app, so actually I have 3 of them in my collection - can I play with it in ITS tournaments and what profiles can he present (suppose Tretiak Anyat only - or is there any other options?) Also would be nice ti have suggestions over the roster with him (cause seems to me anyat for example do not fit well in rosters due to the high point price)
There is a game mode that allows the use of generic SpecOps. (see ITS documents for reference) You can select your SpecOps form here
They're right at the bottom of the list on mobile. Treitak is the old name for a Morat Vanguard Spec-Op, and Corax is free of name for a Shasvastii Nox Spec-Op. They were also both intended as "Universal Proxy" miniatures for missing profiles and loadouts. Anyat and Hasht are named special characters whose fluff ties them to these troop types, like how Sargosh is Jayth character.
unless you're the organiser of the tournament, make sure that tournament has the spec-ops extra, otherwise it would be illegal to have a spec-ops in your roster