Yes, if the customer wants the elephant on the shirt, the creative artist will have to draw the elephant, but a creative artist will put nice touches to the image and make it jump off the shirt. This artist should be able to work up lots of ideas or thumbnails for you to choose from. Computer skills are important, but frankly there are a lot of artists who still use traditional methods and then have computer artists do the separations. It depends on your needs, but I would rather have super creative and weak on computer if those were my choices. Don't expect this person to do every style.
Flexibility is an important attribute here.
Not all art is screen print friendly and the artist who insists that it is printed the way drawn may be too demanding for your production and profit needs. Get this artist into the shop to see what is involved with making minor changes to an image. I did a consulting job for a very large company and worked with a staff of 20 artists and designers. Art Director This is the top job. I think you need to work up through the ranks to be the Art Director.