The trainee manager at a fashion design store in Hamilton took a unique approach to life with her passion for people and boxing.
But the 23-year-old's life was cut short when she and two others, Jake Lindsey Hayes, 19, and Connor James Swetman, 17, perished in the house fire early on Saturday.
The trio were unable to escape the inferno at a 95-year-old villa in central Hamilton, which broke out about 5am.
Four others, Joseph Soutar, Michael Heyes, Raine Tarawa and Bayley Reid, managed to get out amid exploding gas bottles, thick smoke and intense heat.
Mr Johnston said the family was grief-stricken at losing its youngest member.
"We know that Toni has left a huge hole in not only our lives, but in the lives of many."
A statement from the family of Jake Hayes thanked those who had helped or been at the scene and left tributes to the teenage car enthusiast.
They said their thoughts and hearts went out to the other families affected by the tragedy and thanked fire-fighters for the grim task of bringing "the kids out of the house in what were awful conditions and circumstances".
Jake's would be the first of the three funerals tomorrow while Miss Johnston's and Mr Swetman's would follow on Saturday.
Mr Swetman's aunt Leanne Otto told the Herald the family was trying to cope as well as they could and support from outsiders had made a huge difference.