Woohoo. I figured it out! It was a fundamental understanding of how timelines interact with each other. I'm now a tiny bit less of a noob than I was a few hours ago. Not really a symbol issue, either.
I'd love to share the hype document, but it has some proprietary info from a client. Best bet will be for me to make a quick sample, if anyone is desiring it.
Added: I should say, however, that I didn't solve it exactly the way I described it. I ended up doing a 10% opacity on the image which worked for this situation (click to bring to 100%). The issue with the plus and it overlapping the graphics is still something to mess with for sure.