1. It's still kind of meaningless, as you apply the Posions to your weapons to use on an enemy, and it is too easy to make a potion that has no negative effects to need to put any points into it.
2. Yes, the Alchemy Enchantment reduces the Cool Down Timer on Potions. So, while it does not lengthen the time, it allows you to use them more often. Use the Oru Essence. Also, I don;t think you get any more reduction for a higher level glyph with this one, so try a few different potencies and aspects before you make it. Since we can now use lower level glyphs on our gear, this may be one time it makes sense to make a low level glyph for high level gear.
Enjoy the game, life is what you really want to be worried about.
PakKat "Everything was going well, until I died"
Gary Gravestink "I am glad you died, I needed the help"
However, for the second question, I was wondering if the enchantments had an effect of the time of poisons, not potions. I use rings and such to lengthen potions (like invisibility). I was wondering if it did the same thing for poisons. I tried putting the same rings on and the tool tips don't change for the length of time on the poisons, so I think the answer is probably no.