I've never heard anyone asking for "future in-status" documents. You need to provide documents that prove that you've been in-status so far. In fact, if you apply for college, and get I-20, your OPT will be cancelled, and you'll be out of status. You cannot be in OPT and full-time F1 student at the same time. This is what I got from my Intl Student Advisor last year. Do consult your ISA. Ask your lawyer to provide you references where such a rule is stated.