Thwack 

Boko's voice echoing into his mind, Thwack replies with "Terry thinks it is keys, but he no recognise Terry. I follow him anyway." He goes on to inform the others of the pink haired man's plan of splitting up with his entourage. "I go with keys but someone maybe go with other guy."

((Roll for duration of Psi-whispers 6))

At that, the duo stops. False-Kei nods at his companion, a weather-beaten human man in his 60s with a massive scar across one cheek.

False-Kei pulls a long, slender knife out but then rests his arm against his side. "You two." He glowers at Thwack and Peri. "You two go that way." He points south-southwest down a dark, narrow alley, in a direction leading loosely back toward the bridge to the High Quarter. "Before I get hungry. We're all done with your company." His partner is silent, staring at Thwack before spitting on the ground. There are no other people immediately around at this point, although Gerrard, Boko, and Qivys are approaching at a distance (and may roll a group stealth check to remain unnoticed if they want to.)

Gerrard attempts to be stealthy:  20

Boko stealth: 22

“I think it is time we force the issue with this one - can we try to demand answers or get a close look to confirm?” she says over whispers.

Thwack 

"I not know what keys look like. If we wait 'till he alone will be easier to ask questions, yes?" Thwack replies.

When maybe-Kei demands that he and Peri must head back towards the High Quarter he almost heads off without question, the man's tone so commanding. He stops himself before heading off. "Me can help you! I good at sneaking if that's what you need. Have to make up for dirty boots" he pleads, trying to endear himself to the pink haired man.

"Agreed" is Qivys response to Boko. the dwarf hastens his steps to where they saw Peri & Thwack go. 

"No no no no no..." says False-Kei quietly to Thwack. "No help, no sneaking." 

He turns to his companion and nods. "My friend here will escort you." 

The older man grips Thwack's shoulder firmly and begins to march him down the alley.

False-Kei turns to Peri. "I know you from somewhere?"

 They don't yet notice Gerrard, Boko, or Quivys carefully approaching.

When Qivys gets close enough he will use Minor Illusion to create a sound of something crashing on the other side of Kei.
His hope will be he can cause Kei and his companion to look that way and the rest of the group can rush them. 
If they look in that direction Qivys will rush in and punch Kei.
Attack: 14
Damage: 4-unarmed damage. 

The noisy illusion catches them off-guard, and Qivys rushes in for the punch. The limber False-Kei grabs Qivys' arm and lurches it away.

Roll initiative!

False Kei: 17
False Kei's buddy: 3

(We'll presume Gerrard and Boko are 30 feet distant.)

Qivys initiative: 12

Gerrard Initiative:  8

Thwack 

Qivys' spirit of the moment attack catches even the keen eyed kobold off guard. Thwack prepares to join the fray.

Initiative 12

Boko initiative 12

”We are attacking them?”

Initiative (reordered):
Thwack: 24
False Kei: 17
Boko: 12
Qivys: 10
Gerrard:  8
False Kei's buddy: 3

Thwack, still gripped (but not restrained) by the older goon, may act first!

Thwack 

Years of avoiding the wrath of task masters finally pay off. Thwack senses the wild swing coming and nimbly acts first. He let's out a (Draconic) cry that sounds like a mix between a feral cat and a squeaky cart wheel. He shakes off the goons hand and moves aside 10ft. He will hold his action until he sees what his companions do (ie after Qivys acts). He will cast Fear on maybe-Kei (Wis Save 14) hoping to have the man run away from him and into the waiting arms of Gerrard and Boko.

((Draconic Cry: As a bonus action, you let out a cry at enemies within 10 ft. of you. Until the start of your next turn, you and your allies have advantage on attack rolls against the enemies that could hear you.))

Thwack concentrates on a Fear spell, but holds back its arcane force, waiting for his companions to act. 

False Kei shrieks shrilly and slashes at Qivys with a small blade.

False Kei Knife Attack vs Qivys: 10. Hit: 4 piercing damage (and make a DC13 CON save...)

Everyone except Thwack may act. Gerrard and Boko are still 30' distant down the alley.

"Thieves! Robbers!" shouts False Kei. "Murder! Fire!"

Qivys dodges False Kei's attack.
"Tha real Kei wouldn't have missed!" he taunts the imposter. "Take a nap!"
Qivys throws a bit of sand in the air and casts Sleep (at 3rd level)
9d8: 47

Gerrard:

Moving up smoothly, Gerrard draws his weapons as he goes and reverses his grip striking at the Kei look-alike with subduing blows.  If one of the blows lands, he attempts to knock the weapon out of Kei's hands.

(If Kei is already asleep, apply the attacks minus the disarming to the goon with him).

Subdual with rapier:  Attack: 29 Damage: 14

Subdual with rapier:  Attack: 24 Damage: 9

Subdual with dagger:  Attack: 29 Damage: 11

Added disarm if an attack is successful:  DC 17 Strength save to avoid, added subdual damage:  10

Boko races forward and casts hold person at third level on both Kei The False and the Goon.