@Jeannie - back to that tweak. I understand what you were saying about the copy now. Though note if you hold the mouse down on that button I referred to on Edit Metadata it can copy in the other direction.
But you should really do yourself a favour and do these steps:
(1) Put that pesky tweak back in to say "copy". Trust us. Please
(2) Install the "Quality Check" plugin, using Preferences -> Get Plugins
(3) Any time you see books for an author that are FN LN in the library view, select them and choose Quality Check -> Fix -> Swap author FN LN <> LN, FN
That's all there is to it. No copy/pasting required. Assign a keyboard shortcut to that particular action and you don't even have a mouse click.
If you don't change the tweak, you will get bitten sometime
.
I won't comment on the rest, I've said enough about it elsewhere