Four of the six men charged over the fatal fracas, which included the stabbing of Canberra Comanchero commander Pitasoni Ulavalu, have now admitted to their roles in the incident.

None of the quartet were accused of killing the bikie boss.

On Tuesday, western Sydney brothers Matthew and Osaiasi Kupu both pleaded guilty in the ACT Magistrates Court to an affray charge, as did Canberra man Maximilian Ellis Kurt Budack.

Budack also pleaded guilty to assault occasioning actual bodily harm over what was described as a "vicious" attack on another inmate while he was behind bars on remand in Canberra's jail.

Prosecutor Luke Crocker told the court "some significant footage" of the July 2020 events at Kokomo's would be played at the trio's sentencing, which may take an entire afternoon.

Magistrate Louise Taylor listed the sentencing for June 29 and ordered pre-sentence reports for all three men.

The trio's pleas on Tuesday followed one of their co-defendants, who cannot be named for legal reasons, pleading guilty last month to an affray charge. That man will be sentenced in May.

The others charged over the Kokomo's incident are Frederick Elijah Mercy Tuifua, and another man who cannot be identified because of a court order.

Mr Tuifua has pleaded not guilty to the murder of Mr Ulavalu and is yet to enter pleas to further charges including one of intentionally inflicting grievous bodily harm on another Comanchero, Zachary Robb.

The other man denies a charge of affray.

Court documents show all six men charged over the Kokomo's incident made their way there from a birthday party in Red Hill.

Within minutes of their arrival at the venue, Budack began arguing with bikies Mr Robb and Shane Houghton, who were already there with their fellow Comancheros Mr Ulavalu and Taniela Tai.

Kokomo's security guards intervened in the dispute and threw Budack out of the nightspot.

The rest of the birthday party group left with him, but they returned a short time later and confronted the Comancheros.

Police allege that Mr Tuifua was armed with a knife, which he is accused of raising in the air while rushing at Mr Houghton, who is said to have fended him off with a chair.

During a subsequent melee, according to police, Mr Tuifua raised the knife again and plunged it from behind into Mr Ulavalu's neck, before also allegedly stabbing Mr Robb in the left thigh.

Agreed facts tendered in the matters of both Kupus and Budack on Tuesday detail the trio's respective roles in the nightclub brawl.

The documents reveal that Matthew Kupu repeatedly punched Mr Houghton in the face, while Osaiasi Kupu punched Mr Robb in the face and body.

Budack also punched Mr Houghton in the face, as well as shoving multiple Kokomo's security guards during the commotion.

Budack, who was arrested after being shot three times in a suspected reprisal attack, further admitted to taking part in an unprovoked attack on an Alexander Maconochie Centre inmate while on remand.

Agreed facts show he punched the victim in the face while the man was already on the ground in an exercise yard, being "slashed and kicked" by four fellow detainees in November 2020.

Budack remains behind bars ahead of his sentencing, while the Kupus are on bail.