Characters and Costume Design

I currently have 3 characters in mind for my solo piece. The first is a scientist at the research lab, where the audience will be taking their 'tour'. She is going to introduce them to the show and tell them about what the company are researching (improvements to health and well being, longer lifespans etc - all lies!) She will only be present in the foyer before the show, as she will be interrupted by a message on her earphone alerting her of an 'escapee in lab 12', she will then leave and the audience will be guided into the theatre by FOH.
The next character the audience will meet is the Savage. She is going to try and communicate with the audience and attempt to trade her sticks for audiences possessions (nothing will be taken off stage - she will give everything back!) The Savage has been brought up after the nuclear war and has no concept of the English language, so she communicates using her own various tribal-style grunts. The savage exits as a siren sounds and a voice-over explains that this is means that scientists are out looking for new 'volunteers' for their research.
The third character is a girl (aged about 12) and she has just managed to escape from the science lab where they were doing tests on her. She is hiding in an old den she used to live in with her sister and explains to the audience what really happens in the lab.The scientists say they are trying to create a perfect world where no-one will ever need medicine again. But in reality, they are putting 'volunteers' through painful tests in order to find the right genes and chemicals needed to create an immortal race.To make an immortal human, they impregnate female 'volunteers' who grow and give birth to them. When an immortal baby is born, however, the mortal mother dies due to the overwhelming levels of chemicals the child has left inside her. The girl (test subject) tells the audience that she is going to wait in the den for her sister to escape from the lab, before complaining of a stomach ache and showing the audience her scarred belly.