Can I suggest an alternate route??
1) Rogue1, SA 1d6, Trapfinding, lvl1 Feat: TWF, Human Feat: Weapon Focus: Dagger
2) Swash1, Weapon Finesse
3) Rogue2, Evasion, lvl3 Feat: Point Blank Shot
4) Swash2, Grace +1
5) Swash3, Insightful Strike
6) Assassin1 (or Avenger1) SA 2d6, Death Attack, Poison...