Good news, everyone!
It appears this was caused by bad batteries. I have three Photive brand batteries and one Canon battery. When the camera "bricked" I had a Photive battery in. It read fully charged. I replaced it with another supposedly fully-charged Photive battery. Still the camera wouldn't turn on.
Right before going to bed last night, I had a feeling it may be the battery, so I placed my Canon battery in my charger overnight. I inserted that battery this morning, and the camera turned on!