I was a dual student. Great option if you ask me. Will be practicing both an able to renegotiate salary and benefits. Competition isn't as stiff as strictly PT however once accepted as a dual, the school won't let you switch to only PT because that's a sly trick that some students attempted to pull because the dual option isn't as competitive. They will however permit to switch to OT only.
Typical questions such as Why dual? What is the difference between the two fields? Practice answering that question b/ that will get asked. Why PT? Why OT? Why is professionalism important? How do you plan to maintain balance with the stresses of grad school and life? I suggest to stress professionalism because that is the foundation of the school. The curriculum is very demanding, stressful, breath taking,overwhelming, etc but you learn sooooo much and have the potential of becoming a pretty legit practitioner!! Persistence should be stressed as well. Please don't go in with an arrogant attitude but be confident in ur answers. It doesn't matter if you were a physical trainer all ur life, a PTA, COTA, etc, It doesn't increase your chance of getting in, it's all about how you present on that day. Good Luck!!