It sounds like all you really need to handle names reliably is to ask for the entire name in one field, then have another field for their preferred name (which could be the first name, or the middle name, and a diminutive). And if you need to do something more formal with a title (like Mrs Lastname), potentially have that as a third field.

Sometimes the dumb solution is better than trying to be clever, and it saves some trouble with localisation.