“I wonder if the Kalpoe boys are Muslims.”
Yes. I can’t place their facial features to guess their origin. They could be Muslims.
It would help to know from where (country) the name “Kalpoe” originated.
The CNN news story said they're Surinamese (Suriname -- formerly Dutch Guiana in South America). The population is quite a mix per Wikipedia: East Indians (37%), Creoles (31%), Javanese (15%), Maroons (10%), Amerindians (1%-3%), Chinese, Boeroes and Jews.
Because of the great number of ethnic groups in the country, there is no main religion. Christianity, both in the form of Roman Catholicism and variations of Protestantism, is dominant among Creoles and Maroons. Most of the Hindustani are Hindu, but they also practice Islam and Christianity. The Javanese also practice both Islam and Christianity. At 20% of the population, Suriname has the largest Muslim community by percentage in the New World.