I hate long quotes but in this case I have a reason to quote your two posts fully. Let's see them first and continue after them:
OK, let's start about that highlighted part in above quote. I am now assuming that with no longer booting to Admin ID you mean it will no longer enter the Audit Mode using the built-in administrator account, but that is contradicted with what you mention next, that Backup refuses to run telling it can't be run in Safe Mode.
The Audit Mode is basically nothing more than a variation of Windows Safe Mode; for all things important, Windows considers itself being in Safe Mode as long as it is in Audit Mode. Therefore the Backup will not run in Audit Mode (Safe Mode).
Other than that I have to say honestly that I understand very little of what you have posted. Deleted accounts and such, stuff you should absolutely not do while customizing Windows in Audit Mode.
My sincere recommendation is that you restore your Windows 8 system from a system image, upgrade it to Windows 10, then if you decide to try this one more time you really concentrate to first read the tutorial through, then watch the video (second one in your case) pausing and going back whenever you have the slightest feeling that you did not get something. Proceed only when you think you completely understand the procedure.
There's nothing much I can do to assist you at the moment, simply because your explanation about what you have done and what has happened is for me really difficult to understand.