Thanks for the quick feedback this morning!
In a last ditch effort because nothing else was working I unplugged all HDMI sources from the TV, and left the TV power unplugged overnight. This morning I plugged in the TV power, powered it on, then plugged in each HDMI source. To my surprise, it was working again!
The only thing I can think of is a handshake issue sent the HDMI ports into a "confused" state and they stopped functioning properly. Regardless, I logged a Samsung service request and heard back from the service company by 9:00 am this morning. That's quick service!
I explained the problem and the owner of the service company recommended we replace the main board just to be sure.
To make a long story short, I got it working again but there is no clear reason as to why it occurred in the first place.