I'm planning on having ghost shrimp and neon tetras in the same tank (20g), however I don't really want a lot of ghost shrimp.
I currently have 7 neon tetras. Would they eat the baby ghost shrimp, hopefully keeping the population steady?
Neon tetras will indeed eat baby shrimp. So they can be used for population control.
But keep in mind that you do have to try to keep some of the babies alive. Otherwise you might end up without any shrimp after a while.
From your other post, it seems like your tank won't have many hiding places for the shrimp. So you might want to add a few real plants and moss (shrimp will love this) and a shrimp cave.
Especially when shrimp are shedding their skin, they are more vulnerable and also need a more quiet place to hide.
According to my experience and this article, yes your baby shrimps are going to have problems. Look basically if it fits into a fish mouth it's gonna be eaten. Baby shrimp have no rough shell and no ability to quickly jump away. Even with all the hiding spots available, they are going to be hunted by tetras. So better put small baby shrimp in another tank until they grow up.