Well, this is a tough question for me, because I find proportions ultra tricky.
I do find that for myself, the best all-purpose jacket (if there is such a thing) hits around the hipbone and has some shaping at the waist. Jackets shaped like that and that length can usually be worn relatively successfully with pants or with skirts. Assuming a straight skirt; I think for wider skirts a shorter jacket is pretty much necessary.
Given my own particular shape, I find that longer, boxy boyfriend jackets are very tricky since they seem to cut me in half. And this shortens the leg line. So my solution is to wear them only in a column of colour if I wear them, or wear them open, and certainly with sleeves scrunched. But truthfully, I don't reach for them as often. I do not worry about bum coverage with skinnies.
I like how that Zara one looks on you in the first pic. But you are right, it's not as cropped as on the example. Her jacket seems quite cropped, actually -- almost shrunken. It looks cute on her, and I like the length of that type of jacket, too (my fuchsia H&M jacket is like that, and it's not dissimilar to the J. Crew boy jacket or whatever they call it, although that is not quite as cropped on me as mine.)