I like
Orion a lot. You could use names from the stars in it, like
Rigel, Saiph or
Betelgeuse (you probably think NOT, but it is cool, at least in my opinion), or other constellation names, like
Cepheus,
Draco,
Leo and
Perseus. The moment I see
Orion I think of the stars, so those are the names with similar feels to me. And
Bellatrix, Meissa,
Andromeda and
Lyra would be excellent as sisters for
Orion, but you didn't ask about girls.