The answer was to start the kwalletmanager, go to settings, and uncheck the kwallet enable box. The only problem is that once this is done, some things don't work on the KDE side. Kmail does and so does korganizer, but not kcontact. The other side benefit of doing this is I stopped get korgac error messages when using the KDE Neon desktop.
As for changing the splashscreen back to Ubuntu, I found a terminal command that accesses the plymouth splashscreen settings and allows you to choose which one. I think that whatever you choose is using in both Unity and KDE; at least that's what happened to me.
However, there are still little annoyances when switching from one desktop to the other, a crash from the other side here, a request for a password there. Maybe this is because I'm using the latest KDE from the ppa (5.8.4), but that is supposed to be the LTS version. I do wonder how these would work together if I just used the regular Kubuntu desktop packages from Ubuntu 16.10 instead of the Kubuntu Neon ppa.