Pineapple-Hibiscus Cocktail

Bring sugar and 1 cup water to a boil in a medium saucepan and cook, stirring, until sugar dissolves, about 3 minutes. Add pineapple, reduce heat, and simmer 10 minutes. Remove from heat and let sit 30 minutes to infuse syrup with pineapple flavor. Strain into a small bowl; stir in vinegar. Cover and chill shrub until cold, about 30 minutes. Cover and chill pineapple pieces until ready to use. Meanwhile, place hibiscus in a small bowl and pour 1 1/4 cups boiling water over. Cover and let steep 10 minutes. Strain tea into an airtight container; discard flowers. Cover tea and chill until cold, about 30 minutes. Set aside 8 slices jalapeño and 8 pieces pineapple for serving. Stir mint, lime wheels, tequila, lime juice, remaining jalapeño and pineapple, 1 cup shrub, and 1 cup tea in a large pitcher and chill at least 1 hour. Serve in ice-filled rocks glasses garnished with reserved jalapeño slices and pineapple pieces.