Yup. Mono tracks (for mics) in a session that mixes to stereo is the way to go. The only time to use a stereo track is if you have a true stereo source--some keyboards for example or if you use two mics on the same thing as a stereo pair.
Audition uses 32 bit as an internal mixing format. Why? Because that gives you effectively unlimited headroom in terms of levels. If you mix two tracks together at 32 bit to the point where the clip light is on constantly, you can still just normalise your mix downwards and get a clean, clip free mix. At 16 bit, once the clip light comes on, the mix is damaged. The same advantage CAN apply at the recording tracking stage but most devices (including your mic and my stupid expensive digital mixer) don't support this so recording at 16 or 24 bit is the way to go.
Glad you got is sorted.