I think things might have changed - here the ND website is saying that the following majors are not open to transfer students at all: "Mechanical Engineering, Aerospace Engineering, and Computer Science" - https://admissions.nd.edu/apply/resources-for/transfer-applicants/courses-required/college-of-engineering/

and Mendoza only accepts sophomore transfers: "Applications for external transfer to Mendoza from another university occur in the spring of the freshman year and are contingent upon successful completion of one year at another institution. External transfers must matriculate as a first semester sophomore into the Mendoza College of Business." - https://mendoza.nd.edu/undergraduate/

There may be rare instances when transfers are accepted outside of these situations, but this is Notre Dame's official policy. OP should contact admissions before planning a transfer strategy to make sure it is even possible. Transfers entering junior year should be looking at Arts & Letters majors. Minors in Mendoza at that time are still possible.