Wroe died instantly from head injuries when a 200 kg stone block fell on him while he was demolishing a stone archway at the site.
Wroe was working for Wharfedale Finance, owned by Kunz. Other workers on the demolition job were employed by Yorko 150, which traded as Britannia Construction, a firm owned by Smith.
The court heard that Kunz, of Leeds, had failed to appoint a planning supervisor or experienced contractor on the job and had allowed work to start before an audit had been carried out by the Health and Safety Executive on the site.
Kunz admitted to three breaches of HSE regulations and was fined £65,000 for each.
Smith, of Gomersal, Leeds, pleaded guilty to failing to ensure demolition work was carried out properly and was fined £4000.
Judge Roger Scott described Kunz as "a cowboy builder" who was not competent to instruct his workers on how to do the demolition job.