I have been offered a temporary position as a production Manager for a film project in Alberta. The project will last for between 1 and 8 months. Once I have obtained a temporary work permit for this position, will I then be able to seek additional work once in the country. Also will I need a LMO for such a temporary position. The role is quite specific to my experience.

Based on the title that you describe (which is not always a good indicator), you would require a Service Canada Confirmation to be eligible for a work permit. Such a work permit would be limited to the employer and position for which the application is made, and would not permit employment for another employer or in another position without first seeking a new work permit or change-of-terms.