(decided to move this to another discussion hope thats okay)

I've got another suggestion, this one has to do with squads and npcs replacing other npcs if given and able to;

Replace selected Entity(s)
a boolean that when set true, instead of spawning the entity/npc as a separate entity entirely, replaces other entities listed and thus does not add an additional npc since they have taken one or multiple entity's place.
Selects from a list of entities that are inside the squad given by the player which tells which npcs are allowed to be replaced and which are left untouched.

Example: Zombie squad that always spawns with 4 zombies. An additional npc is added to the squad, i.e. Headcrabs with 1/4 chance of spawning and has a maximum of 3, which is set to replace 1-3 zombies on a successful roll to spawn instead of creating them as extra npcs when the squad is spawned.

variables:

Replace Max
how many Entities are allowed to be replaced, which can stop things like replacing the entire squad with Headcrabs and instead leaving at least 1 Zombie untouched.
Replace Min
given number of Entities that will always be replaced, if able to.

couldn't think of more variables, leaving as is. feel free to add anything you think would fit this idea