Another similarity is, the perp(s) found the victims by going to a trail in a recreational area in the middle of the day.
That is, didn't go near a school, or a shopping mall, or a rec centre, all somewhat more obvious choices.
The Iowa perp, it seems to me, also approached his victims on foot. A vehicle couldn't get close to where their bikes and the purse were found.
Another similarity is choosing to abduct girls from a very small town, less than 5k population. Did the perp(s) count on girls and their parents feeling safer in a small town?
One difference is that L & L were definitely taken away to another location and kept for an unknown time. The Seven Bridges area in Iowa is so remote, a perp would never find girls there, and went somewhere else to abduct them. (But Evansville is not the closest small town)
It's been suggested that A & L could have been taken away, and then returned in the night, but I don't know how much to credit that.
Another similarity, considering the unusual MO above, is no rumours of failed attempts to abduct girls in the area, prior to these crimes. So the perp(s) were...what's the word...not bumblers.