In the Argentine capital, Lalrinnunga will compete in the 62kg youth boys category, while Soren will participate in 48kg youth girls.
In the trials, Lalrinnunga lifted a total of 273 kg and created two youth and junior national records in snatch (126kg), while equalling the snatch record in the senior section.
Soren lifted 154kg (67 + 87) while creating a youth national snatch record and equalling the national record of 154 in total.
In April, Lalrinnunga (56 kg) had broken two national records to win a silver and a bronze medal at the Asian Youth and Junior Weightlifting Championship at Urgench, Uzbekistan.
The trials were conducted at the Sports Authority of India (SAI) campus in Patiala.
In the Asian meet, Lalrinnunga had registered his best total of 250 kg to win the silver in youth section and a bronze medal in the junior section.