I was STARVING while BFing so found it really difficult to lose weight until I stopped.
But, I wouldn't worry about being engorged by that point. It really does settle down the longer you BF for. Something I was glad about at our wedding day was that we had time to slip away as guests were seated for dinner for a rest and a cup of tea and a glass of champagne! I'd recommend that to any couple getting married, to schedule a couple of breaks, so it would be all the more important for you.
i would carry on feeding. by a year old they will probably only be on a couple of feeds max a day (most only on morning and before bed on formula so she would be fine with less). you wont be engorged as you wont be feeding so often as on food/ water etc as well by that age.
if you get married at say midday, you can easily feed 1/2 in am, and once early eve/late afternoon if you want (just try getting her accepting milk of some sort maybe from a beaker for bedtime if being cared for by someone else
I fed DS till he was nearly 4. But by 1 he could go without my milk quite happily for long periods. Your DS will be having other drinks as well as your milk by then. He should be fine I imagine.
WRT being engorged, once you're feeding less, you may not get engorged as quickly. Only you will know nearer the time whether it's likely or not. I would advise building some time into the day where you disappear for 20 minutes, either to feed DS, or to express. Perhaps you could make some time between the wedding and reception, while guests are arriving?
The best diet I know (i've lost nearly 3 stone on it in a year) So you could easily loose a dress size in 6 months or so on it is the Paul Mckenna WOE and there's a very friendly and helpful thread on the weight loss club page.
It's easy to follow while BF 'cos you don't eat special food or change what you eat usually (unless you do for health which I do).
It obv. depends how much you'll still be BF then. (my DD2 literally stopped herself when she was 1!). Yr. DS will be weaned almost completely by then as well so no probs. I used to just BF our L.O.s to sleep at that age. Good luck see you on the P.M. thread!
as i would like to drop a dress size by april/May next year (and also Dp) . Atm im breastfeeding my Ds who atm is 19 weeks old. And also...how do i get around breastfeeding on my big day as dont fancying being engorged???!!