My wife is done with her MacBook Pro. I want to convert with me as the prime user. How?

Question

How do I make me the prime user and still preserve her files and apps for our collective use.

Answer 1

Thanks, now I understand. If you have sufficient space on your Mac to import all the files on her computer that you want, then I suggest you network the two together and simply log in to hers from yours (her Mac will appear in a Finder Sidebar, under Shared).
Another hard disk isn't required unless your Mac does not have sufficient free space to accommodate all the files you want to add from hers, but a backup is a good idea if her Mac is the only one containing family photos and other irreplaceable documents.
For documents, drag the contents of her Documents folder into yours, or a separately named subfolder within it for organizations's sake.
To eliminate autofills in Safari, choose Preferences from the Safari menu, and select Passwords. Un-hide them with "Show passwords for selected websites" and authenticate using her Admin password.
You can choose to selectively delete the sites you don't want to autofill. Make absolutely certain you don't need those passwords before deleting them. If there are a great many, I don't know of a good way of exporting them other than to take as many screenshots as may be required.
User pictures at the Login screen can be modified in System Preferences > Users & Groups.
There are many personalization options in OS X and those are just a few, so if you have specific questions, just ask. The above suggestions are cursory ones and very general in nature.