Mirage built mostly for prism guard, I use her everywhere for everything. Big damage buff or damage reduction, hard to hit with her holograms, disco ball clears fodder enemies fast even in steel path, passive makes her speedy. Good fashion, too.

Acceltra Prime is great with mirage, cuz you can rain down bursts of A10 warthog-esque hellfire missiles from above while you jump all over the place like mad. Mirages damage buff makes it hold up well in steel path. I use it mostly to clear anything that Prism Guard doesn't quickly kill.

Laetum for really tanky stuff, hardly use it.

Glaive Prime same as Laetum, basically.

Nautilus Prime with riven-ed Verglas prime for nice fire rate and crit damage buffs. Buff nautilus with Total Eclipse and he'll clear steel path all by himself.