i want to build a specific kind of Bard which has an interresting approach.
I want him to be a Bard primarily but i can change if its really necessary.
Race is Gnome(Knowledge/Linguistic) or Halfling (Stealth)
The Traids are Heirloom (Duelling Sword) and Sword Scion.
The Main Feat Line Should be Dazzling Display with Weapon Finesse.
It should be a sneaky and trickery Combat style.
What i want to achieve at some point is Using Dazzling Display, Shake them and vanish/stealth next round to go for backstabbing.
I want to keep the Bard because of 2 Reason: Knowledge and Bluff/dipl/Intimidate.
I already looked into it and a low LvL Build seems impossible.
What levels are you playing? What level are you starting at?
Note that Rogues are not actually that good at disappearing. A 1st level Magus can more reliably disappear than a 1st level Rogue. However, if you want Sneak Attack dice and Weapon Finesse, I suppose 1 level in Rogue is the best way to get it.
This is a very feat intensive-build. You're aiming for using a dueling sword, dazzling display, finesse, and stealth all in the same character. You'll need 2 levels in Rogue to get Weapon Finesse and Weapon Focus for Dazzling Display. I'd recommend sticking around for 3 so you can ignore your strength penalty to damage and get the extra sneak attack die. Then I suppose you'd dip 2 levels into Bard to get Bardic Knowledge and Versatile Performance. Dazzling Display would be your 3rd level feat. I suppose Toughness or Great Fortitude would be your 1st level feat. Then Skill Focus (Stealth) or Signature Skill (Stealth) so you can sneak around well as your 5th level feat.
So yeah, it's not going to happen before 5th level. Instead of dipping into Bard, perhaps you stay all Bard or stay all Rogue? Rogues have more skill points than Bards at low levels- Versatile Performance effectively changes your skill points from 6/level to 8/level. Rogues start with 8/level. Unless you want Bard spells or want to stay a Bard for longer, you'd be approximately as good as a single-class Unchained Rogue.
The Problem with Only Rogue : no real use of charisma.
The Problem with Only Bard : to many extra Feats.
I already saw the Problems in this Build but the Fun playing it is unimaginable. First distract the Enemy and then you send your "regards".
Vanish is a 1LvL Spell and can initiate your Stealth after Dazzling Display.
Dazzling Display and Vanish can't be used in the same turn- you'd need Quickened Vanish to be able to do that.
Rogue has no special uses for charisma, but you can still use the standard uses. Perhaps Ninja would be a better option? Ninja gets better proficiencies than Rogue, gets a ki pool that you can spend to vanish or get extra attacks, and also gets Sneak Attack.
Are you allowed to use Performance feats? Because something like a Ninja/Weaponmaster using Performing Combatant can pull some crazy 'performances' in real fights, like using Hero's Display to fear-bomb with a swift action in battle instead of needing a standard action. Crossed with the Shatter Defenses feat and Vanishing Trick you've got a lot of ways to work in sneak attack.
The fun thing about Vanishing Trick is that it takes an attack on a shaken target with Shatter Defenses to open it up to sneak attack; if you have Vanishing Trick, then that first attack can also be a sneak attack. Plus Vanishing Trick is really just fantastic to use defensively between rounds.
Actually, on a Ninja or Rogue with the Scout archetype and Cornugon Smash or Enforcer, you can go Sneak Attack Charge + Intimidate -> Vanish -> Invisible Sneak Attack + Shatter Defenses Trigger -> Iterative Sneak Attacks vs Shatter Defenses.