If you already have relevant work experience related to your career goals, the Co-op Office will be glad to work with you to refine or improve the type of work that you have. You may come by to talk with one of the coordinators in the office. They will work with you to put together a realistic plan to help you work toward co-op qualification. However, if your department has an internship course listed as part of their curriculum, your co-op coordinator will work with you to investigate departmental regulations required to participate in their credit course. If you want departmental credit for an internship, you must sign up for both the department internship course and Co-op 001 001.
Companies vary on their approaches to benefits.
That is a question you may want to ask during your interview with the company representative. There is no time limit. Most of the time, the Co-op Office has more jobs than it has students, and students sometime are not flexible in the jobs that they want. As a UTC co-op student you are required to work with only one employer. That is one reason that the co-op program is different from an internship.