I gather that the witnesses you listed, meaning members of Parliament, ministers, and their staff, for example, are allowed to appear in person. I would personally suggest that the wording say that they must appear in person, rather than that they can.
Perhaps this can't be done. The clerk raised a significant issue when he told us what motions were passed by the House.
If we can't require witnesses to appear in person, can we at least ask them to make an extra effort to appear in person? This would make things easier for the interpreters and for the whole committee. We could avoid some of the issues or delays caused by a poor connection, for example.