Vash as a character is completely open source and public domain. Do whatever you want with them. Change them however you want. Anything at all. Sell them for money.
Vash is an escapist from everything that can be escaped. They will seek out ways to "break out" from whatever container they find themselves in. Anyone that could be described as wanting to "get away" is considered Vash-like. These traits align often with the themes of being observed or judged and of being imprisoned and of being unable to change or escape change. Refusing to play by any rules, Vash tends to be both playful and professional at once or in close relation. Vash is typically associated with the color purple and related colors such as magenta or roses well as materials like lead and mercury.