As for the flax, you'll need to be at Rank B with Tsuyukusa (or at Rank C to buy cotton seeds. If you ship 100 or two-hundred -I forget which- cotton, you will unlock the flax seeds earlier). You'll need a textile mill (I think, the farm circle that makes cloth) and a lot of blue flowers for the dye to make the thread blue. Lavender works, so buying it from the general store in Westown is easy.