dangol,

Including your current OPT I-20 that states the OPT start and end dates should be sufficient for now. I don't think including the receipt for OPT is also necessary as that might just create confusion.

If they need the copy of your OPT EAD card or your SSN or any other document, they'll send you Request for Further Evidence (RFE). By that time hopefully you'll have all your documents in hand. So don't worry about that now and file with your OPT I-20.