I’ll answer your last question first:
You can get this placement from the URLs, it may not be so obvious if you’re using the Desktop version, but you can right click on any link in Manager and Open in a new tab. There you will find the URL paths:
That would be the text string in between / and ? characters.
This should work for any view screen.
Well, that would be totally up to your personal preference, you could argue for it being the last column or maybe even just before Qty column.
It’s totally up to you.