"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.
[Paul Carder]"Now, I've turned on the collapse transformation icon on my precomp, but when I got to do the same to the layers inside of the precomp, I don't have a collapse transformation option on the layers."
There is no "collapse transformations" switch for layers. (Vector layers have a "continuously rasterize" switch in the same location, but that's a different function.)
Enabling "collapse transformations" for the comp's layer in the main comp should be all you need to do.