1A will give no credit after 16B, but that does not mean that 1A credit will be dropped if you take 16B.
I cannot imagine any of the options you are looking at would look good to a medical school application reader, when compared against the desired case of taking your 4 on AP calculus, taking 1B, and earning an A or A+ in it, or taking the 10A and 10B sequence and earning A or A+ grades in them.