You have diagrams? Most straight dudes just use porn...but whatever floats your boat...
I dunno, we haven't actually seen the diagrams Dorian draws...
... plus the dreaded short hair (it's in a braided crown...
I've always thought that was a headband. Her hair would still look fabulous without the weird braid thing. From the first moment I saw it I thought it was an odd choice (from the devs). The braid doesn't seem to be attached to her other hair, unlike say, Josie's updo.
Also, I don't think enough time has passed between the end of DA2 -- the three year gap after Hawke walks away when Cassandra interrogates Varric -- for her to grow hair long enough to be braided in such a way. If you are suggesting that it's some sort of circular cornrow type of thing (I have no other way to describe this), then that idea seems silly. Doing that would require hair maintenance, especially for her hair type, that I rather doubt Cassandra has the time or inclination to do.