1. They will not issue you a social security number just because you are on F1 status. F1 students must have employment before they will issue a social security number. So change to F1 will not guarantee that your wife will receive an SSN.
2. All schools require TOEFL, even the community college. However, you can apply to the language programs to learn English here.
3. OPT is allowed only if the employment in OPT is related to the field of study. For example, if your wife majors in computer science, her work in OPT has to relate to computer science.
4. An SSN is not a prerequisite for employment. In some cases, you can work and get paid without having an SSN, but I don't think you qualify.