Very rarely in Aliron shop, also a little more frequently in Elven Capitol shop. Occasionally in dungeon chests. Same for Blue Moss, though I've never seen it for sale in Aliron. I haven't looked through the code that specifies what each shop sells or which dungeons can yield these ingredients.
+ 2 both; Pays to shop around a *LOT*; Save ur gold (get to CW ASAP!) & buy rare stuff when/where u can find it. (check shops daily!) Even if u don't need it now, you might later on---& many things need a large amount.
Salvia is often for sale in the shops of the Plains villages (like Millford). It isn't guaranteed to be in stock, it seems to be there about half the time. If you are desperate, send one character to each of the Plains villages, and have them stay overnight to refresh the market if necessary.
my reccommendation is, buy a slave <4strenght, give him shackles and put him/them into the towns, especially the elven capital/beast village sell billions of those. Blue moss mainly from Alrion as mentioned before, the saliva is pretty abundant in the other settlements though.
