1. Are any of the Creative Commons licences appropriate for him to use on his introductory text? 

The Creative Commons BY-NC-SA and BY-NC licenses are appropriate for his introductory text, as both allow for others to build upon his work (with attribution), but are non-commercial.  The main difference between the two licences is that under BY-NC-SA, any derived works are to be licensed under the same licence conditions.

2. Do you know of any other licences that he may want to use?

Professor Williams may be able to draft his own Open Licence.  However, this may not necessarily be a simple task.  It may also be possible for him to use an Access to Knowledge (A2K) licence
 

 
3. What permission, if any, does he require to be able to share the materials with Professor Masaba?

• Selected student research and assignments;

Since the students are the copyright holders of work they produce, Professor Williams will require the students to licence their work to him, using the appropriate Creative Commons licence, such as BY-NC-SA.

• An electronic copy of an article written by him and published in an all rights reserved journal that his university library has made available on the university intranet under a licence from the publisher; and

Professor Williams will require permission (ie a new licence) from the publisher, who is the copyright holder.

• A translation of the above translated by Professor Williams.

 
4. Does it make a difference that his colleague is based in the UK?

Due to agreements, such as the Berne Convention and the Universal Copyright Convention, which protect copyright holders rights internationally, it makes no difference that Roger's colleague is based in the UK.