Generally Accepted Rules of Etiquette
Pepperite references as our guide of etiquette The Crane's Blue Book of Stationery. The information is offered as a guide to help in choosing the correct wording for your invitation. We will not alter your copy and accept responsibility for producing the invitation only as copy you provided.
When should I use "honor/favor" or "honour/favour"?
Honour and favour are the British English spelling of honor and favor. There is no difference in meaning. In practice honour and favour are used when the ceremony is taking place in a church; but, either may be used when wording your invitation.
Is it proper to use middle initials?
No. Proper names should always be written out in full, including middle initials. If your fiance or father absolutely refuses to allow his middle name to appear on the invitation, drop it altogether and just use his first and last names. Your invitation will look much nicer without initials.