* I'm French and a French company made me an offer to work in the US. It will sponsor an E2 visa for me. Could I ask for an H1B instead or is an E2 mandatory in this case?

* Is the E2 visa transferrable from one employer to another?
For instance:
- What if I get laid off at some point? How long can I stay in the US to find another job?
- If I want to find another job while I'm still employed by my current employer, could my new company sponsor me for an H1B visa, and how long would it take?

* I'm married, and my wife is currently working with a J1 visa. Would she have to switch to an E2 visa when I get mine, or could she stay with her J1 visa while I have an E2 visa?

Thank you.