Thanks all. I didn't plan on it looking just like the JPG. That's just how the vector ended up after playing with the pic in Photoshop and tracing it in Illustrator. My plan was a light blue shirt with the black in the image being navy and the grays being intermediate shades of blue. So based on what I've heard here, I can do that with halftones.
But I'll probably play around with the colors in Illustrator to get a rough idea of how the two options would look. And also try it with two colors, white and navy. With a light blue shirt, plus the white and navy with halftones, I'll probably be able to get something cooler than just halftones. Thanks.