How do I copy one layer that has text from an inkscape document and past it in another and still maintain all the text positioning?

Hi.

With Ctrl+C and Ctrl+Alt+V you can copy and paste in place, between opened inkscape documents too.

If you want to copy/paste complete layers, try to open the svg with a notepad, copy the group
,

and paste it to the other svg document's right part.

It will place well everything between documents of the same sized borders.
But once they have a different page format, objects are shifted vertically, due to the origo in the svg codes is at the top left corner.