The employer's letter, the bachelor's degree with transcript, proof of Canadian citizenship and evidence of the temporary nature of the appointment. The teaching certificate is supporting material, not the credential relied on.
The degree is the credential; everything else is support
Hypothetical example: a Frontenac Islands instructor assembles a folder with her Ontario College of Teachers certificate on top and her degree buried underneath. The order matters less than the content, but it signals what she thinks the case rests on, and the listing does not mention teaching certificates. The bachelor's degree diploma and an official transcript should be first, because the officer must see a baccalaureate.
The employer letter follows, stating that the post is a faculty appointment at a post-secondary institution, that a baccalaureate is required, describing the courses she will teach, the salary and the expected duration. Her passport establishes citizenship. If she has published course materials or holds a graduate diploma, those may be included but are not required.
A one-page cover sheet that names the profession, cites the degree and lists the enclosures helps an officer who is seeing a college application for the first time that day. Hypothetical example: A Frontenac Islands mathematics lecturer has a university offer, but her transcript lists a degree in an abbreviated form. A first review should match the transcript, diploma, and employer letter to the same name and degree.
The registrar’s explanatory letter settles an unclear abbreviation. If the employer changes the course load or job title, obtain a replacement letter; handwritten corrections create avoidable questions.