Don't matter if the prey is top. middle sor bottom. Rest assured Aplochelius lineatus will make a meal of them at one stage. I would say Platties would be a little on the large side but if the cherry barbs are small then I suggest they would be at risk. You say your fish is only 2" at present, at that size they will not pose a threat especially if they are well fed on frozen and flake foods, but as they get larger then sure as eggs are eggs the neons will disappear.
Regards
BigC