Wow, what a difference in the colour of the pants! That's false advertising, if you ask me!
I'd expect the length to be wrong (as a shorter person, I always know I'll have to hem or cuff or cut off). But I understand your frustration on all other counts.
Online shopping has a real learning curve. I find it works best if I know the line and know my size in that line and if I can send back without cost or fuss (or at least without significant cost or fuss). None of which is easy or guaranteed. Really detailed reviews from reviewers who tell you enough about themselves for you to make an educated guess whether their comments are actually relevant to you also help! But again -- these are not always available.
I got pretty good at online shopping as a matter of necessity (no real bricks and mortar options where I used to live) but have lost the knack a bit since moving to the west -- and at exactly the wrong time -- just when Covid hit and there was really no other way to shop for a while!
Sorry you didn't get the outfit you'd been hoping for but the conception looks great and I know it will come together in time!