I do see that. If you use 40" of fabric, the diagonal length would be 56", with the straight edge seam staggering down through it. So there would be several pieces that are of significant length, 40" - 56". If that is not enough, you need to get 3-4 yards, do the diagonal cut. Fold the fabric with the diag as straight edge & rotary cut your precise width cuts. Every piece would be 56".
I do understand your OP question is about cutting so wide & trimming. I agree that is a lot of fabric waste.
:-D I come off as "too" helpful sometimes. Hope I did not offend. Your project is ambitious & it looks like you are having fun (isn't that the whole point) & I am confident they will be stunningly lovely!!!
As the strips are bias and it is a hanging, and thus will not be washed much. What about a straight cut on your bias strip, and just butt them? The cut will be bias also, so no raveling.
And the most recent question, about her head. There are several intersections with bolder lines, do your head transition there? The earrings, and that 3 triangle unit are bold.