Help! 485 - F1

I am on H1B and will be laid off soon and I just filed my I-485. I-140 hasn't been approved. I want to go back to school full-time. Thus I want to change from H1B to F1. Is it possible to get the approval for status change at INS? Or almost impossible due to my immigration intent? How will INS know I've filed 485 when they process my H1B - F1 change request?

Also, a company may allow me to work in the evening and sponsor my H1B. If so, can I go to school full-time in the daytime on H1B?

Thanks so much for any help!