I haven't tested it, but common sense tells me it's this way:
- Dodge is independent
- Mirage gives enemies 15% miss chance
- Ember Explosion gives them 40% miss chance
each attack, numerous calculations are done:
- Enemy miss chance - takes highest number - 40%
- rolls 0-100, if it's 0-40, attack is missed and rolls 0-100, if it's 0-15, rolls again (Mirage doesn't say how high the chance to set off-balance is). Otherwise (aka rolled 41-100) it means that enemy will hit, which now asks if YOU dodge:
- rolls 0-100, if it's 0-20, you will dodge, otherwise you get hit.
So I'd say you'll have 48% chance to evade being hit, of which some really small percentage will set enemy off-balance.
I'd say it's not really worth it, considering you waste 3 abilities on this, of which only one deals damage (small one at that)