All of the deceased, who are still yet to be formally identified, suffered gunshot wounds from weapons licensed to Mr Miles.
The family has been remembered as "lovely people" who were "deeply connected" to their community.
Cynda's social media profile shows she loved op-shopping and sustainability, referring to herself as a "waste warrior".
She ran her own business called Cynda's Soft Salvage, with items such as bowls and vintage bags named after women in famous songs like Maggie May, Cecelia and Lucille.
"I love fabric and buttons and brown paper, and I really don't like waste, so here is my little business creating useful and pretty stuff to help you navigate life without plastic and a whole lot more," she wrote on her business Facebook page.
Days before her death, Ms Miles also posted about making boomerang bags and had earlier posted a reminder about gifts for Mother's Day.
Augusta-Margaret River shire president Pamela Townshend said Cynda was a loved and very active member of the community.
"She was involved in Transition Margaret River and a lot of activities around sustainability and the environment," Ms Townshend said on Saturday.
"She had a deep commitment to the environment and she'll be so sadly missed."
Katrina's Facebook page lists her employment as "parent of four beautiful children".
At one time, she used a Global Autism Project banner on her profile picture, which said the autistic community deserved more than just awareness.
Part of the banner read: "Accept. Empower. Appreciate."
There are unconfirmed reports her children had autism.
One woman who lives in the Margaret River townsite with her family, but has a property in Osmington, described the tragedy as "scary".
"It's just such a small community so it's impacted everyone," she told AAP.
"The family is a really big part of the community."
According to a Gumtree advertisement posted on Wednesday, Peter Miles was looking for "vineyard and farm work" in the area.
"I have over 30 years farming experience and over 12 years vineyard experience," he wrote.
"I have extensive handyman abilities and experience with a wide variety of farm equipment, can repair fences, and tidy up the property from storm damage.
"I have lived in the Margaret River area all my life and welcome all enquiries."
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