Surely all this material is MT cannon, and therefore by default Traveller cannon. Yes, we cannot reproduce it in a sourcebook. But, what stops us from obtaining usuage rights. Surely, DGP as a licencee would have to aknowledge the propertial rights of main game system which MT (copyright: GDW, now Marc) and therefore, they are protected in terms of not reproducing it but not usage.
Otherwise, design your campaign around DGP concepts letting your imagination fill the rest. Plus, didn't GDW aknowledge many of the events in DGP's formulations in TNE. And, TNE belongs to Marc, so what is the problem, trace it back to things like the Regency Sourcebook or Arrival Venegence.