My battery died, so in order to replace the battery I had to crawl back into the trunk and push that little lever to release the door latch. Now that the battery is installed, the door will not open when I attempt to open it from the outside. I hear a noise from the actuator, but nothing happens and the door will not release. Any insight here would be great. The door worked fine before the battery died.

All other doors open, lock and unlock just fine using the key fob and triggers in the car.

 

I'm not actually sure what latch to which you are referring, or what procedure you used. But, what if the little lever you used to release the door is stuck and didn't return back properly?

 

This could very well be, but I crawled back into the back to see if I could adjust the lever again, but it seems as though there is not a reset function. It's a small metal piece that you lift up with your finger and then push the door open.

 

My daughter used to have a 2011 CT200h which we bought as CPO in 2014. If you are referring to the rear hatch door not opening, had the same problem. You can hear the selenoid click but the hatch doesn't open. Used to lubricate it often, but still happened. At one point, under extended warranty they replaced the selenoid. Guess what?
Still happened from time to time anyway more so in the cold weather or when the hatch hadn't been opened in a while.
My only advice is to keep it well greased and if it jams on you, push the door back down a little. Hit the switch again and try again.
It was annoying as hell but never found a 100% solution.