PS4 Issues Resolved · 6:54pm Dec 7th, 2017
It was the WiFi.
I got a LAN cable in a package of Christmas presents the other day (ordered WITH, not AS one) to see if I could pin down this problem once and for all. Today, since nobody in the house is actually actively using the computer, I was able to get under there and hook up to the router and run it back to my room. Immediate success--quickly signed into PSN, and am now redownloading all my content onto the new hard drive.