Warhammer 40k Tau Is Aun'va Aloud to have 24 Fire Warriors?

Question

Like the Question is Aun'va aloud to have 24 fire warriors since he has 2 honour guard ethereals. Also do those fire warriors also get the +4 cover save and toughness 5?

Answer 1

No.  Aun'va and his honour guard constitute a unit in their own right and don't behave as an independent character, so they can't join a unit and don't convey their advantages to any other unit.

If both of Aun'va's honour guard are killed, then he reverts to being an independent character and can then join a squad of Fire Warriors, but does not convey his 4+ invulnerable save to the unit.