Edina's husband Waris Ali, who is Rana's father, was also on the trip to Pulpit Rock, just south of Ardlui.
The two families can be seen laughing and posing for the camera in pictures taken near the banks of the loch hours before the tragedy.
In one heartbreaking picture, Raza is seen helping an adult steer a boat as they enjoyed a day out Scotland's largest loch in the sunshine.
A Police Scotland spokesman said: "Police were called around 6.40pm on Saturday, 24 July, 2021 following the report of concerns for people in the water near Pulpit Rock, Ardlui.
"A multi-agency operation took place and sadly, three people were pronounced dead at the scene.
"Formal identification has still to take place but the family of a 41-year-old man, 29-year-old woman and nine-year-old boy have been made aware.
"A seven-year-old boy was taken by ambulance to the Royal Hospital for Children in Glasgow and is currently in intensive care."
HEATWAVE TRADEGIES
It comes after a string of deaths emerged as people cooled off in rivers, lakes and canals during the heatwave.
A man in his 50s or 60s was also found dead in the Grand Union Canal in London. Cops have been unable to identify him or inform his family.
At least 30 people have died in water during the 32C heatwave.
Mum-of-two Natasha Core, 30, drowned saving her son, nine, from a lake.
She got him to shore in Lough Gowna, Co Cavan in Ireland on Wednesday night but did not emerge herself.
Her brother Jason Mooney said: "She was an outgoing person, a good mother, she was all for her kids, down to earth – she was just a lovely person. She was taken too soon. She died a hero."
A schoolboy, 11, drowned at a park in Stonehouse, Lanarkshire yesterday.
And teen boxer Frank Varey, 16, drowned in the River Dee, Cheshire on Thursday.
He was found after a seven-hour search. A video emerged of him jumping into water with his pals just hours before he went missing.
A friend said he"tried everything I could to save you", adding: "Please everyone, stay out of the rivers."
Professional World heavyweight champion Tyson Fury said: “RIP Frank. Was a future world champ.”