If the US miles haven't posted to your account yet, contact MP Customer Service (using the web site or calling in) and explain the flights, dates, etc. They'll want you to mail or fax in copies of the boarding passes; that should be all it takes.

DL miles can no longer be credited to MP; this I believe ended around two years ago. You could take those DL BP's and use them to request credit for the flights to a SkyMiles account, though ... if your MP # is on them, they may be reluctant to credit them to SkyMiles, but you can point out that they obviously couldn't have posted to MP.