Here are the damage types that each kind of rat is most vulnerable to:
Guristas: Kinetic then Thermal damage
Blood Raider: EM then Thermal damage
Sanshas Nation: EM then Thermal damage
Serpentis: Kinetic then Thermal damage
Angel Cartel: Explosive then Kinetic damage

1. (Faction) Burrow / Drone Collection (easiest)
2. (Faction) Hideaway / Drone Cluster
3. (Faction) Refuge / Drone Assembly
4. (Faction) Den / Drone Gathering
5. (Faction) Yard / Drone Surveillancev
6. (Faction) Rally Point / Drone Menagerie
7. (Faction) Port / Drone Herd
8. (Faction) Hub / Drone Squad
9. (Faction) Haven / Drone Patrol
10. (Faction) Sanctum / Drone Horde (hardest)