They are all OK except that you need to replace the comma with a full stop. The choice depends on what message you want to communicate. Option 1 works in every situation whereas the other options will need to be amended according to your circumstances. I would say (May 14) to avoid possible confusion e.g. 5/11 means 5 November to Brits and 11 May to Americans.

It is helpful with out of office notices to specify the period you will be absent. To me, if someone says they are on annual leave, I would expect that to be for a period of two or three weeks. However your examples suggest that you will only be absent for one day? I don't believe that it is anyone's business to know why you are absent, so if it was me, I wouldn't say why I was absent, just that "I will be out of the office from x to Y dates. For urgent quotations, please contact Charles (and then provide Charles' contact details).