Acho que seria "vão ao trabalho // vão para o trabalho // vão pro trabalho".
Depending on how formal/correct you want to be.
Yes. Conjunto de dança = a group of people who perform together. Estou usando um conjunto = The lerson is wearing a shirt/blouse + pants which match and are sold together. Trabalhar em conjunto = Work together like a team.
A very word-for-word translation, which I think is still valid, would be "work in conjunction". It's just a wordy way of saying "together", and in English it sounds very formal.
But in English we can say two men and it's good written, why here is an error? The two men is not common
"Two men" can be any two men. In this case, it is "the two men" because it refers to two particular men.