[Pathfinder] Vigilante build advice

[FocusWolf413]

I'm building an avenger vigilante and I'm not sure how I want to execute the rest of my build. The rest of the party consists of an archer ranger, a blaster sorcerer, and a generalist wizard. I'm the guy on the front line, so I need my build to be survivable. My primary objective is hitting enemies to apply debuffs to them so that the ranger and sorcerer have an easier time dealing their damage, but a close secondary concern is actually dealing damage. We're playing 1-12 and I'd like the build to be playable throughout.

Current stats:
Human Vigilante 3
S 14 D 18 C 13 I 12 W 10 C 14
1 Weapon Focus: Kukri
1 Enforcer
1 Social Grace Intimidate
2 Lethal Grace
3 Power Attack
3 Morphic Mask

From here, I'm not really sure where to go. One thought I had was to do the following:
4 Fist of the Avenger
5 Ascetic Style
5 Many guises
6 Favored maneuver (Trip) or Shield of Fury
7 Hurtful
7 (Some Social Talent)
8 Signature Weapon - Bonus: Cornugon Smash
9 Critical focus
9 Skill familiarity
10 Dazzling Display
11 Disheartening display
11 (Some social talent)
12 Violent display

I'll be able to power attack with a keen merciful kukri, make two intimidate checks, and if either one lands, on a 15-20 I'm highly likely to frighten. Fist of the Avenger interacting with Ascetic style isn't kosher but the DM will allow it because it isn't that powerful. Ascetic style will let me add the FotA damage boost to my kukri, as well as allow cheaper weapon enchantments because I can double dip with a magic weapon and an amulet of mighty fists. Keen, merciful, and cruel are pretty important to this build. The problem is that these feats delay the really cool parts of my build by two levels. Critical focus also helps me reliably land crits, and therefore the frightened condition, but I feel like I can do better. Finally, there are some really neat vigilante talents, like shadow's speed, rooftop infiltrator, and shield of fury that all would work great with the mechanics of my build.

I had another idea:

4 Shadow's Speed
5 Hurtful
6 Cornugon Smash
7 Dazzling display
8 Signature Weapon (Bonus Disheartening Display)
9 Critical focus
10 Violent Display
11 (Some intimidate feat)
12 (Some intimidate feat)

I'm very aware that both a unchained rogue and a swashbuckler pull this off far better than I do, but the social talents of the vigilante are a huge draw. I'd like to stay in the vigilante class because of those. Can I have some build advice?