my question/proposal: Can I make Administrator 2 (Users\MyFullName) a Microsoft Account by using the same email address as I'm using for Adminstrator 1 on Microsoft.
Yes, you can't have 2 users with the same MS acct on the same device. Let me make it easier to understand by referring to MS email user as MS and no MS email user as non-MS. AFTER you make MS Admin 1 another standard Local Acct (Sign in with a Local Acct instead w/o an email, write down password)) and with desired User name first, then make it an non-MS Admin 2 (still no email acct). Copy all the file explorer folders (Music, etc) from MS Admin 1 to same non-MS Admin 2 folders.
In Accounts while signed in as non-MS Admin 2, delete MS Admin 1 (you'll be asked to confirm file deletion). Reboot, under Accounts go to 'Your info', select option to 'Sign in with MS acct instead', enter same email as before, to convert non-MS Admin 2 to MS Admin 2.
Will it inherit all the privileges and settings of Administrator 1?
After you have followed the steps, MS Admin 2 is now the only Admin so, yes. All the installed programs have no restrictions and Firefox has your profile under AppData/Roaming and your data files will be in proper folders.
I do this process for people who setup Win 10 with MS email and un-desired name is 1st 5 characters in email address, say, George Nutsinger has
gnutsinger@###.com address becomes user 'gnuts' instead desired name of 'George'. I make 'gnuts' MS Admin a standard Local Account, named 'George', make it an non-MS Admin, delete the 'gnuts' acct after transferring folders data, then convert non-MS Local Admin 'George' to MS Admin 'George' by entering email and pass. Done. Now open C;/Users and George will appear vs 'gnuts'. Good Luck