corporate-wage-slave

The fourth example strikes me as illogical, but it does not seem to me to breach any rules of grammar. The second one is interesting - many Quakers (and others) would tend to use the second form to avoid the use of titles, along with the Mrs/Ms/Miss. minefield. That would in any case be deemed a potential breach of etiquette rather than grammar. Potential, since it would depend on whether the recipient would deem it to lack courtesy. I once wrote a letter of complaint to the then editor of The Independent, using the form "Dear Andrew Marr", and he replied personally, by return and using the same style of salutation - which I remember more than the content of his reply!