From WiCWiki

The Quick overview

Juicefiles are where all the props, houses, nodes, slots and units are scripted into the game. The table below describes what is scripted where.

Juice file	type of objects	juice file location
Propsdatabase.juice	Props, houses, fences, vehicle, bridges	Database\
Unittypes_wic.juice	Units, drivable vehicles	Units\
Nodes_props.juice	Signs, roof props as nodes	Juice\
Nodes_slots.juice	Slots nodes	Juice\
Nodes_wreckfx.juice	Wreck nodes	Juice\
supportweapons.juice	Support Weapons and some specials	Maps\

Where do I change the number and types of members in a squad?

File: unittypes_wic.juice / unittypes_wic_singleplayer.juice

Entry: XXX_SQUAD_XXX/myParasites/Squad/mySquadMembers