Artist to digitize sketch for Class shirts

I need help making specific digital changes from a sketch to a digital image. I am medical intern and and making T-shirts for my class. I have the designs with the changes I would like made. All of the skeletons will have a tattered medical white coat with stethoscope on and replaced the beers with coffee mugs. Two of the The designs have mock up sketches. However the third just not but I would like it the same as the others with the tattered white coat, stethoscope around the neck, and coffee mug in hand. I would like it to still remain in the same style and coloration as the original design with the alterations added. I would need this as a PNG with the transparent background. Please feel free to ask any additional questions