Same here. I guess it is essential to have either Sentinel Mayan or Astra. Anyhow, I have build two teams:

Team 1 (Level X on Auto)

VHE (Guard / Immortal)
Green Mayan (Echo / Advantage)
GPD (Angel / Power)
GD (Boost / Strength / Advantage)

Team 2 (Level IX on Auto)

VHE (Guard / Immortal)
Astra (Fate / Energy)
SDG (Health)
WUR (Guard / Strike)

Good luck in finding a replacement for the two girls.