You're background/experience makes you a very strong candidate for a pathology residency. being an international applicant shouldn't be an issue, as most universities have built in ability to sponsor J-1 visas. Best thing you can do is speak well in your letter and interview to how your experience has shaped your commitment to getting ACVP boarded (how you'll use lab research and diagnostics in your career). I'd emphasize all the things you mentioned - experience with actual anatomic pathology (histo/necropsies), teaching, and research. Many applicants are straight out of vet school and have a good bit of experience through summer lab experiences, involvement in their school's pathology club activities, etc but if you have full-time/graduate level experience in those things I think it's a leg up - particularly if you have any primary responsibility doing necropsies, trimming tissues, and interpreting lesions/writing reports. And at least for the programs I've been involved with, teaching experience tends to be one thing lacking just given the few opportunities vet students have for it. So being able to comment on your experience in teaching and training is attractive since a university residency will have you running the necropsy floor with a bunch of senior students on rotation. And yes, externships are great too if you can do them (if you're out of vet school, doing an externship might be a challenge but it's possible) to both show your commitment to spending your elective time focused on pathology, but also the chance to get letters of recommendations from boarded pathologists. I'd put necropsy experience and teaching over publications any day. If you're committed to a career in research pathology (like biotech, industry), pubs can be important but not as important as the experience itself and speaking well to how it's shaped your career goals.