Aren't this lady's quilts interesting. I haven't seen this fabric before (not in my town anyway) and I would have overlooked it - no imagination to see what can be done with it.
Do you have the same fabric shown in the quilt? If not you will have to match the yardage you have with that in the 'pattern'.
If you go ahead with this fussy-cut quilt, I agree all measurements need to have 1/2" added for seams.
Also be prepared to add a bit more to what will be the outside edge of those set-in triangles, as I think you will be left short if you just cut a 6 1/2" square and cut once or twice on the diagonal
Hope you show us when done.