I think the transform Ashbeast scrolls can only be found in loot (one or two may be sold as well in the monastery). I never encountered a rune of it. I think this just a bailout spell for any fight that is too difficult. Your character can easily maul through any combat in the game with them, which is why they likely just made a limited number of them.
It is not a good idea to be doing both staff and sword fighting. LP is very limited in the game so you need to focus in on one (any one) to be able to reach mastery of a fighting discipline.
Alchemy can be upgraded to 3 in Chapter 2 by anyone who trains alchemy, or by Abrax in the monastery.