hey, i would not bother trading. Keep kin 1y03!
Just because you do not have core 4 for chem, you can pretty much register in any core, and just attend the one that fits in your timetable. Theres tons of other students, so its impossible for them to notice (unless ppl are piled on the stairs, then they might start checking ids and such for fire code issues, but thats very unlikely).
Also, because you are in life science, if you can not get bio or chem, they pretty much have to give you a seat! Those are two pretty much compulsory courses for many 2nd yr and 3rd yr courses.
So if I were you, keep it!