Plecos will eat cherries and I believe with all species of pleco that tank is to small so they should be removed anyway. The amanos will eat shrimplets if they have the chance but I have not heard of them deliberately hunting them down just scavenging. All snails are safe with shrimplets as they are just too slow. Flowershrimp or singaporean filter shrimp as they are more commonly known will not harm babies they don't have effective claws and secondly it will starveand outgrow that tank. They are filter shrimp and need a tank which is 30+ gallons minimum imo you can aid your shrimp by placing a platform infront of the filter nozzle an shaking the filter to loosen debris when you see him fanning or use a pippette and squirt daphnia into the filter pump stream but its really not ideal, if you see it picking food off the bottom with its fans then it means its starving and in the long term its fans will be ruined and unable to filter food.