shrimp will either by eaten by the other ifsh...
Crayfish will be agressive and attack your tetras and eat them possibly or even get harsse by the big fish.
Either you can go with species only tank would work great..
I dont know much about shrimp but I have a blue crayfish and he doesnt mind my fish, however all the fish are larger or as big as him, one thing I noticed was that he picks on my 7 inch pleco, hes only like 3 and a half inches! How I see it is if the fish are larger than the crayfish you should be fine. when my fish swim near him he gets defensive not aggresive although my fish are more aggresive then yours(one ate a whole red tailed shark, first day for the rts too!
shrimp may be ok most likely would become a snack and be careful with crayfish they loveee live plants and will totally wipe them all out. Also they will kill fish when they get larger due to aggression but if you get lucky and get a more docile one then go for it but buy tough plants. You can overstock if you nitrates and ammonia are ideal
If you go with the crayfish make sure your tank is well covered. They will use tall plants or anything else that gets close enough to the surface as an escape ladder. Had this happen with one of mine once. Found him down the hall. As for the shrimp, they may become a snack. My tiger barbs love them.