For instance, if I selected Biomedical at UC Irvine and Biological Systems Engineering at UC Davis, will they be able to see that I chose different majors. (Irvine doesn’t have Biological systems). And if so, will they think I am being disingenuous if I select different majors at different schools?
Nope. From what I heard, they don’t see what majors you have applied to at different schools, nor do they care for that matter because they just want to know what major you applied to their school.