Is it permissible to bring a suitor without the father's knowledge to cover the daughters and family, given that the father himself is aware of his difficult circumstances and need for money, and would this be considered a breach of trust?

If your father has appointed you as his agent to acquire a specific factory, it is not permissible for you to disobey him and bring a smaller factory unless he agrees to it. This is because the actions of an agent are restricted by what the principal has authorized. Therefore, either persuade him to change his request, or adhere to what he has commanded you to do.