Quite a variety there! The grey girl looks real nice through her bones and body, but her hooves kinda look like they point in such a way that say her backs are bowed and her fronts are splayed (or are her claws just long?) She looks a little compact though. I'd find a nice long bull that isnt too thickly boned but still has a nice full body.
Your black looks fabulous! She looks nice and long but a bit wasty on her front. How old are they? If they are young, which they look, then she'll probably grow one but her rear looks awfully flat. I dont know if it's the darkness and angle but this one looks a tad masculine. She has some decently big bones so again, a bull that hasnt huge bones whould be a good idea.
That shorthorn though looks real cool with that color pattern (clapping) Though her underline looks the roundest of them all. Additionally she seems tall for her volume and she too is looking compact in her body. Though her feet point perfectly forward and the topline & front + back are great! Her bone size gives her a broader options of bulls but a stout bull whould produce an excellent calf.