Pick up Red Curtain from the floor, take a Sign from the pole next to bar and take the Dart out of dartboard. Talk to Lonzo again (optional) and ask him about ingredients you're looking for. According to him, the black powder is something different than one used in firearms and stimulant can be probably found in Gizmo's room. As for water, Lonzo is not very helpful - maybe Wenzel knows more on this subject. Hannek can also have some information.