Your question is not very clear, and your example makes it even less clear, as it is wrong!
WC is not euphemistic, and not 'pubic' either.
WC is British English, relatively formal, refers to a toilet, and is possibly a little old-fashioned.
Both urine and faeces are more scientific terms. Both would be used in any form of English, although probably spelt as feces in American English. They would not be used in general speech - but perhaps in scientific papers, and formal reports, such as a police report.