A family of Microsoft word processing software products for creating web, email, and print documents.
Charles's answer provided insight into why my header had a second return... because there was already a paragraph mark in the header and when the table was inserted, it forced the paragraph mark below, thus giving me two returns... can you say can't see the forest for the trees:)
FWIW, there's no way around this. Even if you select header/footer text without the paragraph mark and then carefully select the header/footer paragraph mark before pasting, you will always end up with an extra paragraph.
As for the tabs, if you have used "alignment tabs" (see http://www.techrepublic.com/blog/msoffice/use-word-2007s-new-alignment-tab-feature-to-align-text-with-margins/), they will adjust to changed margins.