I’m going to use my warlock models for shining spears, rip one of the arms off and replace it with the jetbike autarch’s right arm to make the exarch’s star lance. Then I’m going to take the farseer off his bike, mount a fusion gun under the canopy, and put the metal autarch on there with another dire avenger spear arm to represent his laser lance. Other than his singing spear, I wasn’t really digging my farseer model anyway; the flow from Eldrad’s body to the jetbiker arms and legs was sort of weenie looking. I’ll keep him around for later.
edit: I added in two more vypers, dropped all their holofields as well as the shuriken cannons from the ones with bright lances, changed the shining spears' exarch to have a normal laser lance and a shuriken cannon, and changed the wave serpent's scatter lasers to shuriken cannons.
Autarch – jetbike, mandiblasters, laser lance, fusion gun
5 x 3 Guardian Jetbikes – 1 shuriken cannon each
10 Dire Avengers – Exarch with twin avenger catapults and bladestorm
Wave Serpent – twin-linked shuriken cannon, shuriken cannon
3 Vypers – star cannons, shuriken cannons, spirit stones
3 Vypers – bright lances, spirit stones
4 Singing Spears – Exarch with shuriken cannon, skilled rider, and withdraw
3 Fire Prisms – holofields, spirit stones