Hello madmuffin, while the visibility of the attachments can be keyed during an animation, the visibility of bones and slots is not.
Therefore I recommend making the particles attachments transparent/deactivated in setup mode, then you activate them in the specific animation that requires them, once you've done that animation, you can make their bones invisible, as this won't affect any animation and you'll have a less cluttered working space.
Key Frames - Spine User Guide