If the swerving cyclist saw the girl's bikes on the trail at 12:20, then the girls had to have been kidnapped at that spot only moments earlier. There was only a 5-12 minute window of time between the bike sighting and the 12:15-ish video more than a mile away. If the swerving cyclist report is correct, then it is not possible that the bikes were taken there by the perp (per police that maybe the girls were never there), as 5-12 minutes is not enough time to kidnap two girls elsewhere, load their bikes into a vehicle, subdue the two girls, drive down the backwoods lane, haul two bikes to the path, toss the bag over the fence toward the lake, possibly re-arrange the bikes and vanish.
If the girls were kidnapped on the spot and the bikes were re-arranged from on the path (12:20) to leaning against the fence (4:00), and no officer or resident has come forward claiming to have moved the bikes, then the perp must have done it later or they are different bikes.
If the girls were taken from that spot within moments of when the swerving cyclist came along, it's surprising he didn't see anything. It must have been happening somewhere close by. I think it's worth noting that this good citizen did not lean the bike against the fence. I think there's a bit of a taboo about touching other people's bikes.