Dynamically populating image/text content in a precomp

Hi,

I'm a long time after effects user, but my main usage has recently shifted from motion graphics to game UI proptotyping.

I'm trying to figure out how to most efficiently build UI prototypes that I can quickly update. A problem I frequently run into is having a list of items (Icons, menu items) that behave the same, but otherwise have one element that is different. In a game engine, the way to do this is to have an object that has all the behavior and static elements built in, but where you externally specify the dynamic texture or text string for each instance when putting it in a parent object, rather than it being hard coded into the child object.

Is there any way to do something like this in After effects, either through expression trickery or some newer CC feature that I don't know about?

My current workflow is to either:

• Make a bunch of copies of the precomp and then change the desired elements and drop them in seperately. The problem with this is that if I need to, say, change an animation from linear to eased, I have to either go change it in each comp individually, or delete and recreate/repopulate the comps manually.
• Put any dynamic elements into the parent comp and try to match them to the motion of the precomp. This basically removes most of the benefit of using a precomp for this because I'm having to re-animate a bunch of stuff on top of my precomps.

Both of these options suck. Please help.