This may be a big D'Oh. Moment. We'll see.
It appears the default router's IP changed. Not sure why things got messed up with DHCP enabled--but I've changed the "hard coded" IP info now. We'll see what happens.
-> Not much. Still seeing unhappiness. I put the router back to the .1.1 address.
Sorta related and discussed here: Chromecast Integration (beta) Stop Working - #13 by rob9
Going to the new hub caused all my Chromecast things to get new IP addresses--and that busted them as well. Setting them via reserved IPs back to the original IP address fixed them.
I actually wonder if the Chromecast app may have been part of the problem--if it couldn't find the devices, it may have consumed resources and/or otherwise messed things up. Guess we'll see. I got the default gateway set back and Chromecast fixed. We'll see if it starts behaving. 
