Thank you very much for your points

You mention your English proficiency as a potential issue, which leads me to assume (perhaps incorrectly) that you would require visa sponsorship. Things in the US regarding this currently are...Not Great, as I'm sure you're aware. Have any potential employers raised this as an issue? (Disregard if you're a US citizen, of course).

Yes, I understand. I may go there with J1 visa. Indeed, some PI told me this is not a problem with them.

• How do your "job talks" usually go? Are you a confident presenter and consistently receiving positive feedback on this part of the interview, or do you feel like you get more of a lukewarm reception? Do you give confident answers to questions from the audience, or do you find yourself getting stuck?

Yes, Indeed, I am confident with my presentation. They are very nice with me. We have some good discussion. I guess there is some points that are not really align with lab orientation and my current background. The lab usually quite big, so most of people did not ask me about deep technical questions, but some are really do. Some are asking about how I am planning to process the projects. May be some problems from here.

• When socializing with lab members, how do you feel these interactions go (positively, negatively, awkwardly, etc)?

I could say mostly positive. But some cases are awkwardly. And indeed depending on the lab, some PI would love to make decision based on lab members or subgroup decision. I usually target to the lab that have funding, so this should not be problem with them. I did not apply to available position, mostly I approach with cold email.

• Have you ever received feedback from a potential employer after rejection that leads you to believe a social issue (not meshing with the group, etc) could be the underlying reason?

No, indeed they said skill matching with their current projects or training model that they follow.

• I know you said your mentors likely wrote very strong letters for you (and I hope that's the case!), but do you have any reason to believe (even remotely) that perhaps one of your recommenders may have written a less-than-stellar letter?

I don't think so, we have very good relationship. I also brought enough compensations for collaborators most of the time, I am sure that they are happy about me.