I know that it follows the Prometheus trend by being titled after the ship.
But some of the new information we've gained from the film is that the Engineers are not a species, but a culture.
It might be a civilisation of various humanoids. I think that humanity was destined to become a part of the "Engineers" if they had passed the test, but we've clearly failed.
With that in mind, the Engineers are a covenant of several species - like Halo's Covenant.
Which begs the question, seeing as they've been confirmed as aliens and name dropped throughout the new novels... could the androgynous Arcturians be another example of an Engineer reject like us that were never destroyed?
By now it's pretty much confirmed that there's other alien civilisations out there, and they're humanoid, and well within reach as three human ships have already reached them - Nostromo, Prometheus and Covenant.
However, contact between species seems to be very rare or not that explored within the franchise but only mentioned in the latest novels and seen briefly in Prometheus and who knows if Covenant will have another Engineer contact with the crew.