Just for funsies; which unit do you think should be IA's designated Spec Ops? WB has Zhanshi, ISS has Celestial Guard, but not all Spec Ops are LI or even all that basic. So which base trooper would you like to see shoulder the burden of supplying spec ops for IA?
Fusiliers are already the Spec-Op for two different Sectorials, so it looks like the Zhanshi will be IA's choice.
I know this is likely going to be true, but both VIRD and OSS are new enough that they might not have had a spec ops designated yet! (One could hope, at least, that a new spec ops ssystem opens up new opportunities)
I think Fusiliers make perfect sense for BIRD as they're AVA Total, it's NCA that should get something fancy, like a Bolt Spec-Op (after Bolts get redone to be awesome, natch)
Note that it is possible to have multiple spec-ops. Look at hassassin, they have both the muyib spec-ops and the ghulam spec-ops. The only common feature for all spec-ops is their ability to link freely with line troops, or eventually something a bit fancier like muyibs if you're lucky. So it kinda rules out Daoying and Haidao. We'll get a zanshi spec-ops at some point, if not now it will be with white banner, otherwise zuyongs are the only option that makes sense.
I expect Zhanshi Spec Ops. I hunger for a Shang Ji Spec-Op. Because BTS 15 would make Haqqislam and Tohaa cry.
Seed Soldiers were linkable in N2, so when the Spec-Ops launched in Campaign: Paradiso the Corax could link with them. This changed somewhere in the transition between N3 and HSN3 and now Corax can't link at all (Hasht is a special case).
But... that's the same guy... his full name is Corax Hasht, and he is the only shasvastii spec-ops...
Hasht isn't a Spec-Op, he's a Dire Foe. It's like the difference between an Indigo and Bipandra, or a Treitak and Anyat. This is a Corax: