hi, I got my GC while in OPT and then OPT Extension. Only after applying did I find out that, if for some reason your 140 or 485 gets rejected, you will be out of status right away which is not the case with H1 because you just fall back to H1 status. I had some scares along the way because of audit during labor process. I guess if you apply right away and with everything working out in your favor you can get your labor approved and then file for 140/485 concurrently to get EADs before December.

My suggestion would be to file for labor immediately and in the mean time also apply for CPT providing colleges. You do have to update your school of any changes to your address or employment because it is something they might look into later. So just send monthly emails to your ISO even if to say no changes in anything or until advised otherwise. If you can still apply for OPT Extension then you should be in the clear. Let me know if you have any more questions.