Repeating 10th grade?

I’m an international student who goes to a boarding school in NE. I am a re-applicant who is considering a transfer to Exeter, Andover, SPS, Choate, and Deerfield. Will my chance be increased since I moved to the States and demonstrated some academic strength?

No. You’re still an international applicant, which always decreases one’s chances.

Possibly. However the AO will probably question what their BS can offer (and you can offer them) that you are unable to get from your current school.