For no. 1,2,3 I have tried this css
#course_component
.wplms_create_course_wrapper .wplms_edit_course_content .course_curriculum_builder_wrapper .vibe_vibe_course_curriculum .curriculum_elements_wrapper .add_cpt_wrapper .curriculum_element_wrapper .control {
display: none;
but it will also hide search on quiz & assignment Course Connection, which I need when admin want to connect it to course after instructor send course for approval. Refer: https://prnt.sc/1ciux0y and https://prnt.sc/1civ6dl