Ok, to help with my knowledge(if you all want it)--

Alchemy: Alchemy is a valid skill, though it is not called or classed as Alchemy. In this game it is the concept of mixing poisons, or perfumes in this case. There are "Antidote" Crystals, but they vary upon the type of poison. Players in the Manga and Anime both spoke of how the players focusing on it were developing more and more powerful types of poisons that caused the Antidote Crystals to delay. They couldn't ever stop being effective as the game programmed them to be permanent, however the stronger the poison the more the crystal needed time to fully work out the poison.

Beast-Taming: In the SAO universe Beast-Taming explanation was similar to the special skills. "One day it just happened to be there.." This happened with Silica in the fact that she randomly happened to befriend Peta when she met her, due to her skill. Beast Tamers get the skill in their list, but it is also somewhat random. There is in-lore debate that the reason it is given is for people who attach themselves to certain monsters, or animals. In my character's case it is his being a hunter both out-of-game and in-game. He will have spent the largest amount of his time in-game becoming a better predator, and thus eventually got the Beast-Tamer skill.