Could I use EAD from spouse's I485 to apply GC

请问xiaobaitu和众大虾:
I am currently on non-transferable H1B, and I do have an EAD from my spouse's pending I485. If I use the EAD to work:

a) Am I still eligible to apply my own employment-based green card as a primary?

b) Am I eligible to switch back to H1B if my spouse's I485 is rejected and thus the EAD becomes invalid?

Thank you so much for your input,