✔ 最佳答案
In answering your questions:
1. You can apply Leave of Absence at any time. However, universities will usually not granting admission to students who recently expereience Leave of Absence. Therefore, the best way for you to do (based on your ideas) is defer your graduation, leave for 1 year then come back to community college and finish the rest (including transfer application).
2. OPT is a one-time one-year work authorization. It is easy to apply. The catch is you must have a job within 3 months or OPT will be invalid. Companies are still willing to hire. The catch is how much they are paying you.
3. In theory you can come back, providing you are eligible for a visa again. However, your academic performance may be discredited when you have not come back for a while. For example, if you come back after 2 years, your academic result can't be considered as it is.
All GPA and credit are valid, but subject to each individual. Some school can reject your GPA and credit if they think they can't represent you anymore.
4. Yes. But they can choose not to recongize any credits as they want.
5. 30 days.
My suggestion to you is forget the OPT. It is not going to worth it.
USCIS, at their discretion, can in fact issue employment authorization to student visa holders based on financial difficulty. However, it is difficult to get. Since you are running out of options, I think you can try this. In this case, you will not need to take leaves and can work and study at the same time.
Remember, you have to demonstrate why you are in financial difficulty. Understand this, lack of money is not a difficulty. School recommendations are also important (your academic results).