As far as I know, there are 4 people that have claimed to have seen the children after their abduction (by another person). One scenario is correct. MOO
...plus a 5th person with no relation to abductor.
There were other alleged sightings in the afternoon and evening.
1. Haydn Phipps (suspect: Harry Phipps)
"Haydn, who was aged 15 at the time of the disappearance, came forward to researchers in 2007 with the claim that he had seen the children in his father's yard on 26 January"
2, 3 & 4. Allan McIntyre (potential involvement) and his children, Andrew and Ruth (suspect: Anthony Munro)
"Mr McIntyre (Andrew) claims there was sand and blood in Munro's car on the day the children disappeared and believes his dad helped dispose of their bodies."
"Max McIntyre, a former Telecom worker, was investigated over the disappearance after one of his daughters, Ruth Collins, made the allegations back in 2007 but police found no evidence he was involved"
"McIntyre's children said that they and their father initially mistook Arnna's body for that of a boy because of her short haircut"
5. Miss Daphne Gregory
"About two-and-a-half hours later (2:45pm) another witness, Miss Daphne Gregory, sighted the children with the man, who she observed carrying an airline bag similar to one owned by Jane"
Man linked to Beaumont children's disappearance dies
Disappearance of the Beaumont children - Wikipedia