This is just a very rough proposal to set the properties of the vanilla squad according to the squad id
some thing patch like this
xxx_squad_1 {
"engineerUnlocks": [1],
"artilleryTypeUnlocks": [],
"spawnCostPerSpawnPersonalScore": [0]
}
xxx_squad_2 {
"engineerUnlocks": [1,2,3],
"artilleryTypeUnlocks": [1,2,3],
"spawnCostPerSpawnPersonalScore": [0,100,200]
}