Xiaobaitu, more questions about H4 use EAD

Hi,

I have more questions about H4 using EAD.

1. If I use EAD only a few months, apply for H1 next April, suppose I485 is still pending before H1 application submission,
can I transfer my status to H1? Do I need apply for H1 outside US?

2. If I485 is denied after my H1B application submission, any risk?

3. If I-485 is denied before my H1B submission and I stop work in company, can I keep my H4 status? DO I need go outside US for new H4?

Many thanks.