No. The Dominican Republic has not had, nor has indicated any future plans for travel restrictions. There are currently no vaccine/quarantine requirements or proof of a negative covid test needed prior to entering. However, a negative test will be required to re-enter the United States which is provided by the resort free of charge.
The resort is all inclusive meaning literally everything is included when it comes to food and drinks. Spa treatments and excursions are available but you will have to pay separately for those.
If you are planning on coming for the long weekend, we would recommend getting there on Friday and spending a few days after the wedding to relax and enjoy a little vacation. If you are planning on staying for a week or longer, whatever day works best for you as long as you make it there by Saturday evening :)
Both men and women should plan to wear resort attire. For men this means khaki pants or shorts would be appropriate with a nice short sleeved button down or Hawaiian shirt. For women, sundresses are appropriate. Barefoot or sandals is perfect as the ceremony and reception will take place on the beach.