I have a question about digital design, particularly for designers who specialize in the field of realistic drawings of people.

I'm in the process of putting together an idea for a book cover, in Affinity Designer. I will then take that idea to a potential designer to make a drawing out of it. To give you an idea, the cover will look similar to the once you find on the Marvel movies or maybe a better example... the Maze Runner - Death Cure, where the characters are all lined up.

I have already found pictures of models that look exactly like how I view my main characters, but those pictures are not ideal to place on the cover, as the models are not standing in the right poses as a want them to.

My plan is to take pictures of my girlfriend to get the right poses for the individual characters. That way, the designer will know how to draw each of them.

Now to the point!

Would it be hard to draw all the individual characters, by referencing the pictures that I found online, and using one model (my gf) to draw the pose for the characters on top of that? In other words, draw someone based on someone else. Also, the visible part of the characters would only be from the hips and upwards, not the entire body.