UnScramble this Word: o e l e k i h m?

Questions

The names of which cartoon husband and wife pair were used in army slang for pairs of medals which are normally worn together?

In Paris, what are Louis Blanc and Etienne Marcel?

The popular name for of which rare butterfly comes from the london Borough in which it was first discovered in the UK?

For what do the letters P&O stand for in the shipping line?

Who composed the Academy award winning song Moon River?