When using commands, such as the set AI state command, while it will tell you when you get the syntax wrong, it wont tell you what the valid inputs are. Having some way to fix this would be nice!

Frankly, the player wasn't supposed to use these commands. They're needed for debugging, as it's not always practical to design an interface.
Besides, there are bugs. For example, if you change the mode from "growing" to any other, the nests will grow indefinitely

So it is not recommended to use these commands.

At the time, I was trying to manually set volcanus off aggressive, since it was my first time starting a run on that planet and couldn't get ready in time for it going immediately aggressive once the starting timer ended

This method won't work. After you set the peaceful mode, the AI ​​will check the conditions and switch the planet back to aggressive mode.
You need to call up the start menu from the player settings and specify the desired time/evolution before the attacks begin