When the Boston Public Schools opened the Margarita Muñiz Academy in 2012, it was a first-of-its-kind dual-language high school meant to address issues faced by the city’s growing Hispanic population. At the time, Hispanic students were both the most likely to drop out of the city’s schools and the least likely to enroll in college when compared to black, white and Asian students. They still are, but as the academy enters its sixth full year, its student outcomes are drawing praise from a variety of sources, even while administrators note that steep challenges remain.