Tommy Viktor Söderlund and Johan Sebastian Ljung, both age 26 when the incident happened, face charges of conspiracy to murder; possession of a handgun and seven bullets with no permit; possession of a handgun in a public area; threatening use of a knife in a public area; and theft of a motorcycle.
The duo have already denied all charges except for threatening use of a knife in public.
The men earlier confessed to the murder of Mr Schantz, 25, saying it was a revenge attack after a business partnership turned sour, though they claimed they did not intend to kill Mr Schantz.
The men were arrested at the Surin Sweet Hotel in Surin last year, where they had apparently gone into hiding after fatally stabbing Mr Schantz at his home inside The Lantern housing development.
The three men had previously been part of a call centre scam operation in Pattaya.
In February last year, Mr Schantz apparently fell out with the group and left, taking with him a list of all their “customers” and delivering it to Pattaya police. That led to the arrest of Söderlund, who was later released on bail.
After a quick search of Facebook, Söderlund and Ljung found that Mr Schantz had moved to Phuket, and decided to pay him a visit.
It took them three weeks to track him down, but they eventually found him living in The Lantern in Koh Kaew, and moved into a house opposite.
When Mr Schantz returned home late on August 1, 2011, the two men confronted him and tried to force him into their house.
Mr Schantz resisted, leading Ljung to fatally stab him in the throat in the ensuing struggle.
“It was an accident,” Söderlund told police at the time.
The two then fled the scene, commandeering a motorbike during their escape.
They initially checked into the Andaman Place Hotel in Thalang District, before moving to Surin Sweet Hotel, where they were arrested. A blood-stained T-shirt belonging to Ljung was found in their room.