Thank you, some more questions

1.So, you mean, no visa type is required either, right?

2. We might be the final case of being self-sponsor. How much would be required at least for one year per person? Is it different in case of it's a family?

3. I guess the visa can be still declined even you hold DS-2019, especially in case of self-sponsor, is it right?

4. How long it would take for whole process (until get visa and entry) in case of there is already a professor would like to give you a no-sponsor offer? Sorry I'm really a 'new hand' on this issue.

Really thanks.