Here's the kick in the @$$ for me. I knew that Chase wasn't supported yet, so nbd, I'll wait, but otherwise, I wasn't watching too closely for what working and what wasn't. I frankly wasn't expecting it to show up anywhere near this soon.
It turns out that Samsung Pay doesn't work with Wells Fargo (yet -- apparently coming soon)...but Android Pay does, and that's my only non-Chase credit card. So even though I now, at long last, have Sammy Pay, I'm still having to use Android Pay!
If there were a face-palm emoji, I'd be using it here.
In the meantime, I can offer another confirmation that the app downloads and installs just fine on a VZW phone that hasn't received the OTA update.
In addition to the sideloading warning, though, I think it's especially important to doublecheck that everything pertinent has been left alone by Package Disabler Pro. For all the issues that have been fixed by turning a lot of stuff off, I've found that a number of issues I've had have been fixed by turning stuff back on.