So you're asking for too much with little to zero benefits for the artists, to not say none to be honest.
Talented artists developed skills based on time, dedication, studies and several hours of practice along the years.
If you want professional talent, know that most of professionals don't move their pencils without compensation for their hard work and knowledge.
Good, so if you have done those then provide examples, the professional art demanded should be accompanied by writting of the same quality, a proper portfolio should be provided from you as well. Or at least to attempt to make yourself worth the time of someone despite you're not paying them.
So you're basically asking for a futuristic (detailed) yet anime-ish style, probably you're also expecting your artist to know how to make tech and other elements to accompany the worldbuilding of it. Again, detailed artwork and on top of that has to be of professional quality.
You're also asking about dynamic poses, different clothing, different body types, so you're not even asking for a single concept art of the three characters that you want drawn, you want several illustrations of them as well therefore, more work for the artist and again, no benefits for them.. For a possible comic/manga project that I bet and hope you're only asking for these illustration to use as resource while you work on the script or building your story. Because if you want someone to draw a comic/manga and as well to make concept art, buddy... that's basically asking way too much.
