Your marriage certificate will be sent by the following, depending on the island, Jamaica: 6‐8 weeks, Antigua: 4‐6 weeks, Bahamas: 8‐10 weeks, Saint Lucia: 6-8 weeks, Grenada 2-3 weeks, Barbados 2-4 weeks.
Unfortunately, Sandals does not offer tuxedo rentals on resort; however some resorts have contact information for local formalwear providers (varies by island). Keep in mind, due to the Caribbean climates, you may want to consider a light weight alternative for the groom.