Best Damage Types by Faction
Guristas: Kinetic (Scourge)
Serpentis: Thermal (Inferno) or Kinetic (Scourge)
Angel Cartel: Explosive (Nova)
Blood Raiders / Sansha: EM (Mjolnir)Rogue
Drones: Varies, but usually weakest to EM (Mjolnir) or Explosive (Nova) depending on the specific target
Mercenaries: Kinetic (Scourge) or Thermal (Inferno)

Best Shield Resists by Faction
Guristas Pirates: Fit Kinetic and Thermal hardeners (heavy focus on Kinetic).
Serpentis: Fit Thermal and Kinetic hardeners (heavy focus on Thermal).
Sansha's Nation: Fit EM and Thermal hardeners.
Blood Raiders: Fit EM and Thermal hardeners.
Angel Cartel: Fit Explosive and Kinetic hardeners.
Rogue Drones: Fit balanced EM and Thermal hardeners (damage types vary)