No worries! I had a hard time finding information too when I applied.
I think they care the most about anatomy and physiology and medical terminology. I don't think a B in would hurt your chances of getting in. As long as you passed I wouldn't retake a course. I know a few EMT's, now paramedics, that got C's and still got in. It's always nice to have a little gpa cushion.
There was a guy in my class that was a lifeguard with Ocean Safety, it helped him during skills testing. Personally, I think it's good experience and should help. If you can, take BLS for healthcare providers (American Heart Association) It's just CPR plus a few other things added on at the end. It's offered at KCC. You could also try volunteering at Straub, Kapiolani Pali Momi or the women and children's hospital.
The interview was pretty straightforward. There were about 5-6 people on the panel from City and County EMS, HFD, Hickman Federal FD and KCC. They asked stuff like "why do you want to be an EMT" it was similar to a job interview. The prerequisites and the interview are kind of the main things they base your overall score on. KCC's program is intense but it's worth it.
Also, if he's still teaching, try to take anatomy with Prof. Matsuda. I liked his class.