Rechecking the demo shows that the skills work just fine. Can you provide a video clip showing the skill setup in database and plugin and a battle test of it?
Showing loaded plugins would be a plus.
This is a video of the skills in "action" (posted on an old channel because i'd rather not pollute my main channel). As you can see, most of the skills don't do anything at all. Weirdly, Avalanche worked even though it doesn't usually. Also notice how when Snow Pea used Snowstorm, it only hit the one zombie that wasn't in range of the attack.
Here's the entirety of my plugins:
(Though the issues still happen in the demo)
Wait, I found out the problem! One thing all of them have in common is that they're facing attacks. And upon further testing, I found out for some reason, they only work when aimed downwards (the default direction) and not any other direction. This is a graphic showing what I mean.
It seems that the problem is with facing attacks. They only work when aimed downwards, but when aimed up, left, or right they don't work.