The chest-buster shirt is just a t-shirt with the chest-buster sewn in. The Ripley outfit is baggy green/avocado pants found on eBay, a plain white shirt, suspenders strapped to a belt around the upper torso, Reebok shoes, and of course, the “M41-A pulse rifle” with a shoulder strap (men’s fabric belt) wrapped around it.
Everyone loved it, and knew exactly what the costumes were!