By the way, Kingmaker ends at 17th level.
So, whatever I suggest, needs to come full circle by then.
Okay, with current suggestions:
Azata Aasamir(Scion of Humanity)
Str 10/Dex 18/Con 12/Int 13/Wis 8/Cha14
Dawnflower Dervish 4/Standard Bearer Cavalier 1/ Battle Herald 7
1. Enforcer (Blade of mercy & Signature Moves traits)
3. Combat Expertise
5. Butterfly Sting & Outflank
7. Arcane Strike
11. Discordant Voice?
Is Lunge worth it?
If a Keen weapon is not available, would Improved Critical be better?
Also, is there anything else I missed?
Is butterfly sting really worth it (meaning is enough of the rest of the party going to be in a better position to do more damage)? Dawnflower Dervish 12 (+FCB to inspire courage), will be giving you a +8 morale to hit/damage as a static bonus, toss in a +4 keen courageous weapon, that goes up to a +10 morale bonus. That is 2d6+28 damage on a crit (15+ rolls) before counting in PA, DEX/STR or any other possible additions.
Unless most of the party is using x3 weapons, or has better crit riders (don't forget Enforcer causes you to frighten, causing your opponent to run away, provoking attacks for movement and moving out of position on top of shaken), chances are you should be keeping your crits. You don't get to choose who will hit after you crit, so you might be more reliable.
Lunge is iffy for this character honestly, you can go Sound Striker with DD to get a utility ranged touch attack, you can get a ranged weapon (your Dex is high, grab a bow) and arcane strike it to make it magical if needed.
I'd probably go (if you really don't want to go the moonlight stalker route):
Bard (Dawnflower Dervish/Sound Striker) 12
1: Enforcer (BoM, SM traits)
3: Arcane Strike (if you don't have a magic weapon, else swap with 5th)
5: Lingering Performance (make the most of your rounds)
7: Extra Bardic Performance (fuel ranged attacks if needed or swap with 9th if you are feeling squishy)
9: Combat Expertise (your AC might be lagging at this point OR if you can manage a +4 belt of dex/str, Power Attack, more damage)
11: Improved Crit (if you didn't manage a keen weapon by now, else free feat)
And you have full casting progression. Post 12th level you'll need to get a headband of CHA +2 to maintain spell casting (5th levels spells at 13th, 6th level spells at 16th).