A witness described how Mr Diya's wife stayed calm and prayed while CPR was performed on her husband and children.
It is believed the children attended school in the capital, but Praise-Emmanuel travelled on a US passport as the family visited the Club La Costa World resort near Fuengirola.
Spanish police have since allowed the swimming pool to reopen, despite fears the pump system may have trapped the three victims in the water.
It was initially speculated that a suction problem may have turned the pool into a death trap that first snared Comfort, then her brother and father as they tried to save her.
A member of staff who dived into the pool to try to save the family similarly encountered "difficulties" escaping the water, a report by local paper Diairio Sur said.
But the resort said in a statement: "The Guardia Civil have carried out a full investigation and gave formal permission to reopen the pool as they found no concerns relating to the pool or procedures in place, which leaves us to believe this was a tragic accident which has left everyone surrounding the incident in shock."
A later statement said the resort would continue to "co-operate fully with the authorities", adding: "Naturally, we will continue to offer every assistance and comply fully and transparently with any requests made by them."
A neighbour of the Diya family said she was "really devastated" to learn of the deaths of Mr Diya and two of his children.
Speaking outside her home in Charlton, Lara Akins said: "I still can't comprehend it, it's still shocking."
The 59-year-old described the family, who she said had lived in the south-east London close for around 10 years, as "very religious, very friendly, very humble".
She added: "They are so nice, that is why everybody is shocked."
She said she was still looking after Christmas presents dropped off by friends while the family were away.
"They know we are very friendly with each other," she added.
The daughter of another neighbour said her mother "feels really bad" for the Diya family.
Emma Morris, 38, said her 64-year-old mother Pauline Morris knew them as "really nice people".
"They were just really a really nice family, they spoke to everyone here," Ms Morris said.
"They just said hello to everyone, I don't know them personally, it's just what my mum has told me.
"It's so sad, it's such a shame."
A post-mortem investigation found no signs that the victims were intoxicated or had suffered any external injuries beforehand, instead concluding the cause of death was drowning.
The only surviving sibling on the trip had been with her younger sister in the pool just moments before she got into trouble, but showed no symptoms to suggest pool chemicals had harmed her.
Police said they were continuing to keep an open mind on the circumstances surrounding the deaths, stating "all options" were on the table.
Relatives have flown out from the UK to be by the side of the widowed mother and her surviving daughter.
