L1 - frigate/destroyer
L2 - Cruiser, Assault Frigate
L3 - Battlecruiser, Heavy Assault Ship
L4 - Battleship, Command Ship

In Game website with Mission information: http://eve-survival.org/wikka.php?wakka=MissionReports
Asteroid chart: http://www.eve-files.com/media/corp/WLDs/roid_grid.jp

** Main Damage type to shoot at the enemy **
Guristas - Kinetic
Serpentis - Thermal
Mordus - Thermal & Kinetic
Blood - EM & Thermal
Sansha - EM & Thermal
Angel - Explosive
Mercenary - Thermal
Corpum - EM & Thermal
Gist - Explosive

** Damage types ***
Guristas - Kinetic / Thermal
Serpentis - Thermal / Kinetic
Blood Raider - Thermal / EM
Sansha's Nation - EM / Thermal
Angel Cartel - Kinetic / Explosive /Thermal
Minmatar Fleet - Thermal / Explosive