1.) There's not a lot you can make right now with Alchemy or a Gasmogrification.
It would be nice if you could make a base-gas with Gasmogrification, and add some elements to it from Alchemy to mix it into a poison or antidote. You would need Botany and Gardening V though, so it's a high level skill.
2.) Make poison and antidote stackable, like the fertilizing dust cans.