@Pixie26: Well, at least stop reading the wedding sites that treat “wedding etiquette” as a single set of absolute black-and-white rules that exist a) outside of the context of your day-to-day life and that b) don’t take the character of your community and the individual feelings of YOUR friends and family into account. That’s phoney etiquette — but it’s very common. Real etiquette is about smoothing social interactions.
Getting suddenly married while on vacation on a sunny island sounds very romantic. I hope you may be very happy. My mother and father married, unplanned, when they were not engaged (at least not to each other; she was engaged to someone else) and they lived happily together for forty years — may you enjoy one another at least as long.
Despite what you may have heard elsewhere, a “reception” is any party where you “receive” guests — and where there is nothing else special enough going on to take the spotlight. “Receptions” are usually afternoon parties featuring conversation and mingling, since “Dinner” or a “Ball” tend to get called “Dinner” or “a Ball”. You can have one whenever you want, and refuse to take any flack for it: offering hospitality is a virtue, an act of generosity.
Centerpieces, place cards, and dessert are normal at big parties. Multi-tier fancy cakes are not actually restricted to weddings. When I decided to start baking fancier cakes I made them for little niece’s birthday parties and large summer garden parties. There is no etiquette rule whatsoever defining what shape your dessert is allowed to be (this is the silliest rule I have ever seen trotted out in an attempt to ruin the fun of brides who are being accused of wanting “pretty princess days” — itself a hypocritically derogatory term.) If you are having dancing, then music is also normal — wedding or not — and a DJ, band, fiddler, or at very minimum an mp3 player with a good amp and speaker is required.
I consider card boxes to be in dubious taste whether it’s a wedding or not, and photographers are tolerable provided they don’t get in the way of letting the party happen. Actually, you can even quite properly have the first dance of the evening: it is called “opening the floor” and is the perogative and duty of the host and hostess. It won’t be your “first dance as a married couple”, but it is still the first dance of the evening, and it is yours by right.
You are also completely within propriety to wear a beautiful gown in whatever colour you choose, including white. You should not dress in a manner completely inappropriate to the time of day and formality of the event (that’s inappropriate even if you are getting married that day, for all that brides feel free to do so) and you should not dress with the intent of “showing up” all your guests — again, ditto, even if it’s your wedding day. But for an evening dinner-dance, absolutely nothing is wrong with wearing a formal gown.
It would NOT be rude to do nothing at all, but it wouldn’t be hospitable either. And it wouldn’t help build community. And it wouldn’t make your mother happy. And your friends wouldn’t get a lovely dinner and a fun evening out of it. And do you know what? It would not be any “better etiquette” despite the bad advice you have read elsewhere. Because etiquette is all about hospitality and community and lovely dinners and making people’s mamas (and other friends and relatives) happy. Go for it. Real etiquette is on your side.