When In Doubt, Deconstruct
Deconstructed, weddings are a legal binding of two people into the state of marriage. So yes, you do need a marriage license and an officiant. Not optional. Weddings are optionally a ritual that binds two people into the belief and cultural system of marriage via acts of magical significance. So maybe you should have some ceremonial acts. And perhaps some ceremonial artifacts. Weddings are also optionally a celebration of the binding of two people into marriage. If you take this option, you should have some celebration accoutrements. And if you want to celebrate, well then give a mouse a cookie, because all kinds of fresh hell break loose.
You can see how quickly we move from needing a marriage license and officiant to needing strands of crystals hanging from pale blue manzanita branches or custom 4-foot high sand candles or a fabulous Swedish paper cutout altar hanging. How quickly we subsume the theater of ritual to the requirements of a photography schedule. Yes, if you are going to have a celebration, it will have a visual aspect. It will look like something. But that is all you have to know for sure. Nothing says you have to have a color palette or flowers or lighting or signage or anything. Your wedding has to look like something because we are humans with eyes. That's it. But what it looks like doesn't make it more or less of a wedding. Once you take that checklist apart.
All of this has been said before, and said very well. Maybe it matters. Probably so.