Campbell, who had a $130,000 contract to take down the building, faces homicide and involuntary manslaughter charges for each of those who died when the wall collapsed onto a Salvation Army thrift shop next door.
The judge upheld similar charges against Benschop, who was operating an 18-ton motorized excavator at the site just before the collapse despite a warning he received last February at a South Philadelphia demolition job, according to testimony.
A city inspector testified of having cited an unsupported wall at the South Philadelphia site, and of having warned Benschop against using heavy equipment next to an occupied building.
Campbell and Benschop are also charged with reckless endangerment for those who were injured.
Both men have pleaded not guilty and will face trial in Common Pleas Court.
So far, they are the only criminal defendants in the building collapse, but several times, Selber and Cameron made reference in court to an ongoing grand jury investigation that could lead to charges against others.
Tuesday's testimony included no major disclosures about the ill-fated demolition project, an early step in a development planned by real estate investor Richard Basciano, whose company, STB Investments Corp., owned the Market Street property.
Still, the hearing included the first public testimony by architect Plato A. Marinakos Jr., who had obtained a city demolition permit and taken bids on the work from Campbell and two other contractors.
Campbell took the job for $130,000, expecting to make additional money by salvaging wood, steel, and bricks from the site, while the other contractors bid $330,000 and $500,000, Marinakos testified.
In its grand jury probe, the District Attorney's Office granted Marinakos immunity from prosecution for his testimony.
On the witness stand, he described pressure from Basciano and Thomas Simmonds, STB's property manager, to speed up the demolition, in spite of STB's inability to reach an agreement with the Salvation Army to get access to the thrift shop's roof in order to shore up the brick wall between the properties.
"Richard and Tom were adamant about keeping the demolition progressing," Marinakos testified.
He said he visited the site June 4 and was shocked to see a long section of unbraced brick wall, from which all the flooring joists had been removed.
"I spoke to Griffin immediately and said, 'You can't leave this wall like this. This is crazy,' " Marinakos testified. "He said he'd take it down that night."
Despite Campbell's assurances, Marinakos said, the wall stayed up - until it collapsed onto the thrift shop the next day.
Defense attorneys contended their clients were being scapegoated for a tragedy that illuminated failures in the city's oversight of demolition projects.
Campbell's lawyer, William Hobson, asked Marinakos if he sought a $5,000 "kickback" from Campbell for helping him land the demolition job. Marinakos denied that he did.
Daine A. Grey Jr., representing Benschop, said his client was just following orders from Campbell, working from one day to the next for cash.