We are not "formal" and our wedding will be classy but I wouldn't call it formal. It's in the afternoon and the men aren't wearing full tuxes/ suits. It's not backyard BBQ casual but somewhere in between.
1. Do I have to put titles on the envelopes? Mr. & Mrs. Joe Smith or can it just be The Smith's or Joe & Mary Smith?
2. Does the male always come first? I have a lot of unmarried female friends that I'm inviting so it seems weird to send it to Joe Smith and Mary Jones when Mary is really the one I'm inviting and Joe just happens to be her date/ boyfriend. I would find it odd if my friend sent my invitation to Jenna's Fiance and Jenna. Feels like I'm the plus one.
Re: Question on addressing the envelopes
Ms. Mary Doe and Mr. John Doe (married)
Ms. Mary Doe
Mr. John Doe (not married)
You should always use proper titles when addressing mail. You can use informal wording in a letter, but not on the envelope. A wedding invitation is a formal piece of mail, no matter what the level of formality of the event. For instance, if I were writing my daughter, I address the letter to Mrs. David Jones, but I write "Dear Amazon,"