The 12-year-old was enjoying end-of-year celebrations on December 16 when a freak gust of wind picked up the castle and several inflatable zorb balls.
A funeral service will be held in Devonport on Wednesday afternoon at the same venue where schoolmates Zane Mellor and Jye Sheehan have already been farewelled.
The Devonport City Council on Monday said it would collect the countless tributes left outside the school and create a permanent memorial.
General manager Matthew Atkins said the council will work with the families to determine a suitable location.
Peter's mother, Miranda McLaughlin, told the Adelaide Advertiser newspaper people would travel from many parts of Australia for the funeral.
"He was the most beautiful person in the world," she said earlier this month.
"He was full of life. He made everyone smile and his heart was so generous."
The coroner is investigating the circumstances around the accident and will receive reports from Tasmania Police and WorkSafe Tasmania.
More than $1.4 million has been raised for the families via an online fundraising page, while the federal government has committed $800,000 to counselling and support for the region.
"I'm sad we couldn't be friends and I'm sad you all had to go so early," one hand-written note left outside the school read.
"I hope you have a happy spot in heaven."
Two boys badly injured in the accident were moved out of intensive care last week after their condition improved from critical to stable.
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