Gracias. That's what I thought, but then I wasn't sure. (-:
(I meant to post the link: related discussion: Stirbt das Bargeld aus? Erfahrungen aus versc... - #13
A couple more thoughts on the original question:
(2) is more complicated, because if the person holds a specific title that no one else holds, then he or she is the XY, but you can leave off the article 'the.' E.g., 'She has worked as president of the company.' (Vs., e.g., 'She works as a vice president of the company.' Vs. 'She works as vice president for Asian marketing.')
There are also certain occupations that are sometimes used without the indefinite article or written about in a form that resembles headlinese. It may depend partly on the verb, too. 'He appeared as soloist with the XY Ballet.'
I'm hesitant to give anything like a sweeping rule, because I can't think of enough types of examples to generate one. MikeE or someone who has advanced English grammars on their bookshelf would have been helpful on this kind of question; I haven't had books like that on hand the last few years, sorry.