Reading the last part of Dickens' novel "A Christmas Carol" I stumbled on "Laocoön". My query concerns the spelling with the letter "ö". Was it in use at Dickens' time or is there an other explanation?
It is a still-standard way of designating that the pronunciation is /leɪˈɒkɵ.ɒn/ However, many people completely omit such diacritical marks these days , so it it fading. It is intended to prevent people from pronouncing it to rhyme with cocoon!
Yes, naïve and Noël are partly as a result of how they are spelt in French. You might occasionally find them in words not directly derived from French; some American publications still use it in words like coöperation as a way of indicating that the two vowels are pronounced separately, but I don't think this is mainstream any more.