1) In general, either way, so long as its understandable and the relative strength is easily found. We don't care what level of strength you have, really, just so long as you know that most will only fight someone at a similar level. Some use words and others use numbers(for things like explosive power, and such), a mix can be used to the best effect. Mainly the fights are mid-level when it comes to magic.

2) Both. Some use soliders, some use mages, some use fighters. There is some overlap, where a solider may also have magic, for instance.

3) For info on the ranked system, please see the HQ.