I have a Stagger Storm! I run clockworks with it sometimes! Here are things I've noticed about enemies when they're stunned!
• Upon being stunned, all enemies' attacks automatically finish regardless of where they were in their animation, immediately creating the hitbox or any projectiles that the attack would normally create. This is pretty widely known on enemies that have big flashy attacks, like Vanaduke and Lumbers, but actually affects all enemies (so far as I can tell). After that, their attacks function as one would expect.
• Gremlin Thwackers in Tier 2 and above only do their initial strike while stunned, and don't follow it with their second strike. As far as I've been able to see, they don't use other attacks.
• Gremlin Bombers leak grenades while stunned as if they were on fire, though at a very slow pace.
• Mecha Knights begin their charge animation but never actually complete the charge while stunned. They simply revert back to their standing animation when the spin is supposed to take place.
• Alpha Wolvers only bite once while stunned, much like Thwackers.
• Drones can be stunned, but it doesn't seem to do anything.
• Kats do not attack at all while stunned. They just kinda derp about.
They are dropping bombs whenever they are re-inflicted with stun. much like if they were re-inflicted with fire, over, and over. This is due to the nature of mist bombs; they keep trying to inflict they're status, at low, at intervals until it ends.
But yeah... hehehehe...
~Tsu