No. You can cross the border freely. In fact, we'd be surprised if you even noticed the border.
In the North, where Rostrevor is, we use Great British Pounds. In Dublin, and the South, we use Euros. Most places accept card and there's a cash machine in the village.
Not necessarily. You can organize taxis and take buses to get from Dublin Airport to Rostrevor. If you stay in Rostrevor, all of the wedding events & activities will be within walking distance.
No. Unfortunately, you cannot.
When deciding what to wear, think "Mexican-Irish fusion backyard wedding party." Whatever that says to you, go with it. Anything from tuxes to party shirts, gowns to sundresses goes. Festive colors are encouraged.
No, but thanks for your thoughtfulness! If you'd like to get us a gift, though, you can donate to our "Honeymoon Etc." fund via Venmo or on the day.
Rostrevor is considered the Riviera of Ireland, but don't let that fool you, we could easily see 4 seasons in one day. Dress for sun, but don't be shocked by rain. All of the events will be taking place indoors or with shelter.
Beyond your outfits for the wedding day, you should think about bringing clothes to hike in, swimming togs/swimsuits to bathe in Carlingford Lough, and stuff that you are comfortable in. A rain mac/light raincoat, will never go amiss in Ireland. It will be May, but layers always come in handy.