Size matters, and since you won't get your amanos to breed you don't have to worry about baby shrimp. The adults normally would be fine with what you want. Of course if your fish get hungry enough (ie not fed for a week) they might try to eat anything.
I might suggest that you don't get all the additional fish at the same time. You could get a mini cycle with the additional bioload added all at once that could be to much for your shrimp as they are more sensitive to amonia than most fish. I would get the tetras, wait a week get your corries, and the next week the gourami, or some variation of that idea.