479er is a unique case as she is a Face Character in Red Vs Blue. Other Red Vs Blue characters are deployable, although they are mostly all based on actual in game models. Rooster Teeth produces RvB with Microsoft/343i's blessing, so, while her gear is not able to be replicated or seen in game, if you apply specifically as 479er, and provide the appropriate visual reference, I think you will be fine.
However, mixing a Mark V (B) helmet with Naval Pilot armor would not be deployable as that combination is never seen in game or in any publication or art.
There may be a slight misunderstanding. I, honestly, don't trust myself, at my current skill level, to be able to produce something that I would be happy with in the case of helmets. with this being the case, I was actually referring to cast helmets specifically, I apologize that I did not specify.