Does BCB have the guts to make it 4 foreigners? Probably not. They ll worry about the entertainment value, and i bet tournament organizers will influence them, because they really dont have much obligation towards developing cricket in the country. I bet owners will also take pride in fielding big name foreigners over local talent.
At the end guys like Trego, Samuels, etc will end up batting in top 3, and bowl their full quota of 4 overs. All the teams will have 2-3 players who are just there to fill the numbers.