Joe, listed to people who run these crap shoot wheels, not to the sellers
18x9 wheel with 36mm offset:
245 45 18 tire will not rub, but it's not a proper width tire for a 9" wheel either.
275 40 18 tire WILL rub on the lip, unless you use some super stiff shocks AND keep it at city height. Forget about being able to drop it even an 1".
18x10 wheel with 40mm offset:
275 40 18 will rub, unless you do the same as per 36mm wheel above. It might rub less than the 36mm wheel, but then again 275 tire is kind of narrow for 10" wheel.
18x10 wheel with 45mm offset:
same applies, but a possibility of rubbing on the sway bar arises.
To add to the problem, different manufactures spec their tires differently, so one tire in the same size will differ in sectional width from another.
If I were you, I'd buy an 18x9 36mm set with 255 45 18 tires all around.