In my experience, your points about communication and onsite visits are key. Also, communication should be centralized and managed on both sides so there is not only a communication channel, but also clear lines of responsibility. Of course, communication is not just phone and email, but also well defined specs.
However, getting involved in another company's hiring process is rarely a good idea. Most offshore projects are results oriented, so getting involved in hiring is too low level (i.e. micro-management). In other words, manage the output, not the process.
With the above said, involvement in hiring can be effective when 1.) you're using the offshore firm to acquire very specialized, high-end talent, and 2.) you're paying a substantial premium above local market to ensure hiring is a rare event.
However, getting involved in another company's hiring process is rarely a good idea. Most offshore projects are results oriented, so getting involved in hiring is too low level (i.e. micro-management). In other words, manage the output, not the process.
With the above said, involvement in hiring can be effective when 1.) you're using the offshore firm to acquire very specialized, high-end talent, and 2.) you're paying a substantial premium above local market to ensure hiring is a rare event.