Dilshad Shamo and Ali Khdir ran the "sophisticated and successful" operation from a car wash business.
The group is believed to hold the Vietnamese passports of those smuggled into the UK as debt bondage.
Henri Nikolli, 19, from Welwyn Garden City, is jailed for multiple drugs and firearms offences.
A judge tells Ramal Briem he should be deported to Iraq once he serves his sentence.
Europol said more than 450 officers from the UK, Germany and Belgium were involved in the operation.
The seizure "will have deprived organised criminals of millions in profits", the NCA said.
Border Force officers seized a "massive" haul of Class A drugs hidden in banana pallets.
Kamar and Kamran Ilyas will be sentenced at Sheffield Crown Court on 22 June.
Labour councillor Abigail Marshall Katung agreed to buy the home in Sandmoor Drive in Leeds in 2015.
