If you look at the dm_lockdown map, there was (or at least, the version that I had had 'em) an entity right above the holes that controlled the antlions and how many spawned.
I assume it's just an npc_maker that spawns them.
Did you try checking the start inactive flag?And regarding antlions...
I believe if the player places it [the turret] it will activate for the player's team, try it.
Antlions were planned for dm_lockdown but got removed - The holes were left in. And there's a sample dm_lockdown VMF...I think all the ents for their spawning are there, actually. Take a look.
a rabid caged skunk with a stickPoor rabid-caged-skunk comrade D: