My theory on KB4534310 (314.4Mb) is as follows and it's based on the computer doing the exact same thing three times now. This was the 3rd time the KB4534310 install was attempted.
KB4534310 installs successfully via DISM. The required restart fails and the computer goes into system recovery which effectively uninstalls KB4534310. Eventually the computer restarts fine. Which is where I'm at now. The same four required updates are listed, including KB4534310. It's a Catch 22 at this point.
Talk about a head scratcher. CBS file is attached.