It might be a good idea to start with a bigger type of small shrimp ( if that makes sense ) Try Ghost Shrimp . They're bigger than cherries and less likely to be eaten when fully grown.
It might be an idea , when you begin to stock the tank, to add your most peaceful fish first if possible, and then the shrimp, then add some more fish later on when the shrimp have grown a bit and are less likely to be eaten.
If the whole tank is full of small peaceful fish like tetras, rasboros , cories ect, then ading small shrimps like cherries and bee shrimp is fine at any time generally.
Just make sure you have lots of plants for them to hide in.
I rarely see my cherries and Amanos on the substrate despite only having Weatherloaches and cories on the bottom. They prefer to skitter about on the plants and walls, picking food and algae from there.
I used to have a ghost shrimp, and he was much more active on the substrate, full of beans and often stole food from right out of the fishes mouths before swimming off with his prize! I'd love some more but my LFS hasn't had any in for some time.
Shrimp are generally a good thing to have I think. Good cleanup crew, espescially in the case of Ghost shrimp, and they have a very low bio load so their minimal waste won't muck up your water chemistry.