Milestone 1:
Preliminary outline, and color borders under it.
Milestone 2:
add the color... tweak color borders forgotten in Milestone 1

I'm still working on this.  But this is what I have after 3 days.  I changed the pen width from .5 to 1.0 to make it easier to see. Akane's line art is separate from the sister's. Personally, I think Akane looks better (sporty) with this shorter hair style than the longer one 3 years later.