Ferts don't usually cause problems with the less sensitive shrimp. Cherries and most of the other colours of Neocaridina should be ok. Just take some care not to overdose with anything. CO2 boosters like Excel can bother shrimp if you use too much. Just take care not to overdose and you should do fine.
However, Platies will most likely eat the shrimp babies and might even eat some juvenile shrimp too. If shrimp are what you want, you'd be better off with some smaller fish. Maybe danios or guppies, both quite hardy fish. [ not giant danios, they get quite large ]
Gold zebra danios are very pretty, and guppies come in a rainbow of colours now. Kyathit danios look like they have leopard spots on a gold body, very attractive fish. Leopard danios have spots too, but much smaller ones. Long fin forms are available in Zebra and Leopards too.