This can be made to 8 colors. Halftones are just different "tones" of a color made by decreasing the percentage of ink lay. They would be helpful in your case because in areas where, for example, you have your darkest brown, you set that to be the color printing and make all the other browns percentages of that color, so you don't have to have 4 different browns. When printing on the shirt halftones appear as dots, just think of classic comic book coloring, thats how the halftones print. Also, simulated process is another way to get around the 8 color rule. In all honesty though, I don't think you will have to worry about setting a file up for print on this design, but keeping working at it and I'm sure you will get there.