The organisation of collaboration with the external party should ensure that the division of roles and responsibility for conducting the project are clearly laid down and known to all parties involved. The organisation should also ensure that, as a researcher, you have the final word in relation to conducting the project. The arm's length principle also applies here.
Yes, however, it is important to make sure that the responsibilities and roles are clearly described, so that your freedom of research and the arm's length principle do not come under pressure. In general, an AU researcher should be the project manager, but there may be circumstances which make it necessary to have an external party as the project manager. Remember that, as a researcher, you govern the choice of methods and materials, how results are presented, as well as the conclusion of your work, and that this must be clearly stated. Your conclusions as a researcher must not be limited by the external party, and you must always have the final word.
Yes, if the steering committee has no controlling influence on choice of methods and materials, how results are presented and the conclusion because, as a researcher, you must always have the final word. Make sure that this is clearly stated. A steering committee can ensure progress in the project, it should never control your research. Again: Your conclusions as a researcher must not be limited by the external party.