If a transgender (female to male) had surgery to remove the breasts and lymph nodes, would this reduce the risk of breast cancer?

You would think so: But actually not proven. Also, i doubt that the lymph nodes were removed.

Yes.: A mastectomy does reduce the risk of breast cancer. It certainly is not completely gone but it definitely helps.

Probably: In general, transgender surgery does not remove your lymph nodes... Just the breasts. A cosmetic, non-cancer, operation for the breasts can occasionally leave some breast tissue. This may leave you with some risk of breast cancer, but this is probably much less than 5%. Everything still depends on your underlying risk of breast cancer, which may depend on your family history and other factors..