Applying for a B1 visa with the reason to decide whether to pursue E2

Hi There,

I'm currently working at a startup in SF on my OPT. However, I didn't get a H1B and my OPT ends at the end of June. I already started working on my own startup in the US and we just filed an LLC. It's an ecommerce business. My plan is to leave the country to change a visa and then come back to the US to work on my startup. We are not ready to raise fund. We would need 3-4 months to build traction.

Given this, I'm thinking about getting B1 and then if I can raise fund, I will apply for an E2 visa. I understand that I am not supposed to work but I really really want to do my own startup in the US.

1. Is coming back to the US to explore business viability or do fund raising (to apply for an E2 visa) a strong reason for B1 visa? I can have my friends issue a business invitation letter.
2. Is my plan to go home to apply for an E2 visa after the trip enough to convince an officer at the embassy that I will leave the country at the end of the B1 visa?
3. Should I work with a lawyer?
4. Or is it better in my case to apply for a B2 visa?

Thanks so much,