You know I was sitting here trying to remember how I got around some of this stuff at one point, prior to switching some things up, and it finally hit me. Like you I had the UAC down to the bottom level, but was unable to get admin things done even when the user had Admin perms. I stumbled into a program called elevate.exe, which surprisingly enough would put kixtart into a higher mode, but NOT display the UAC, and would allow me to do what I wanted.

I used this one:
https://jpassing.com/2007/12/08/launch-elevated-processes-from-the-command-line/

but also found this one:
http://code.kliu.org/misc/elevate/

An admin script would also be another way around all this, as well as using the Task Scheduler with highest permissions.