When a work has no publication date or page numbers, should I include the abbreviations n.d. (“no date”) and n. pag. (“no pagination”) in the works-cited-list entry?

No. Do not use placeholders for unknown information like n.d. (“no date”) and n. pag. (“no pagination”) unless your teacher asks you to do so.

(If facts missing from a work are available in a reliable external resource, they can be cited in square brackets; see section 5.122 of the MLA Handbook for more information.)