I think with OT, bio is still relevant. I can't speak for sure about the lowest GPA the committee has accepted, but in addition to the general prerequisites (abnormal psych, stats, etc), they also require you to take a second set of prerequisites that you could only take at their school (they are undergraduate courses you would enroll in as a non-matriculated student, but consists of graduate-level coursework). This second set of prerequisites are OT-related coursework (cadaver dissection lecture + wet lab, kinesiology, neuroscience, etc).
If your application is accepted, it will be under the provision that you continue to take and pass these second Mercy-specific prerequisites. If all goes well and you pass those remaining prerequisites, then you start the program that Fall.
Mercy's application process is unique from the other ones in that you're basically taking many of what would be considered first year classes in other MOT programs before you begin the program, but the tricky part is taking these classes and applying does not guarantee you will get into the program, which may deter a lot of people from applying because it is a huge time and financial commitment (takes about 2+ years to take these second Mercy-specific prerequisites and the money spent on them is not deducted from the tuition should you get into the program).
The actual program starts in the Fall and is every other weekend, Friday evenings and all day Saturday and Sunday.