A wedding shoot in a graveyard!?
The idea strikes me as very oblique and incoherent in a way.
I'm not a full time wedding photographer, thus the original question, but don't a good proportion of wedding shoots take place in a church or the grounds of a church? Correct me if I'm wrong but I know some couples prefer to have them taken at the reception venue if it's nicer than the church or church grounds, but that's not the case here and is by no means 'the absolute thing to do' (or is it?). Of course I'll ensure the headstones do not play a prominent role in the photos and I'll avoid it entirely where I can as described above (I have a Nikon 80-200mm that I hope to use for this if possible).