Jones has spent nearly two years repeatedly calling for police to reinvestigate the case, desperate for answers as to what happened to his only child.
This week, police confirmed the review would incorporate many of the issues the father had highlighted.
"It gives me hope that justice will prevail in the end," Jones said.
"It's a step in the right direction."
While it was what Jones wanted, he was guarded with his optimism.
After all, any forensic evidence in the form of fingerprints or footprints would have been lost, witnesses' memories would have deteriorated and many telecommunications records would have been deleted.
If nothing else, it was a concession that the original police inquiry was deficient, Jones said.
"They've finally admitted things weren't done properly."
In an email, viewed by the Otago Daily Times, police outlined the scope of the review, which was finalised after senior officers from Dunedin and Invercargill visited the scene.
A timeline for all sightings of Lachie would be constructed, along with the movements of the boy's family members.
Jones' rejection of the accidental drowning theory is partly due to the fact his son had no marks on his feet and legs, despite supposedly walking a long distance on rough gravel and through gorse and thistles.
Funeral directors wrote a letter to him, saying Lachie's body was in "perfect condition" and there were no visible marks on his lower limbs.
Police have now requested a second opinion from another pathologist about the lack of injuries.
There would also be a review of the decision not to search for forensic evidence around the scene, especially at the gate which Lachie would likely have climbed to gain access to the oxidation ponds.
Timing around the child's disappearance was difficult to discern from witness statements and police estimated at least 12 people would be interviewed to "tighten up" the sequence of events.
Police requested cellphone data for key witnesses two months after the incident, by which time much of it had been deleted.
What was obtained did not fully corroborate statements.
"Consideration will be given to further phone data analysis," the email said.
Jones said he "won't be standing back" when he meets the senior officer leading the review next week.
The review
1. Timeline — clarifying the sightings of Lachie and the movements of family members.
2. Body — requesting a second opinion from a pathologist in respect of the lack of any injuries or marks on Lachie's feet.
3. Scene — consideration of whether fingerprints could have been obtained at the time from the entry to the oxidation ponds area.
4. Witnesses — about 12 statements to be either obtained or updated to tighten up the timings of people seeing Lachlan and the movements of his family.
5. Cellphones — consideration to be given to further phone data analysis.
