The real motivation behind the Endurance is to sow humanities seeds in the stars, with the species continued through fertilised embryos at the sacrifice of those still on Earth. This is born out of the belief that the gravity equation has no solution, something that Cooper's singularity meddling reveals to not be true; science mumbo-jumbo from the black hole means that somehow we can all escape the pull of Earth with ease. At the end, with humanity by the Saturn wormhole and gearing up to head to their new home, it appears the whole of Plan B is rather unnecessary. But that doesn't mean the embryos are going to go unused. Dr. Brand has no conformation that TARS managed to get any usable information from the black hole, so for all she knows Plan B is still the only option. To that end she'd probably try her best to continue the species, bringing the first generation of Edmund's-planet humans into being (assuming the technology exists for this to be done single-handedly). Which poses another question - how does Plan B work logistically? Can the new humans be grown test-tube style, or do they need a human womb? And if it's the latter, why was only one woman sent on the Endurance mission? Potential Answer: Even if she heard about Murph's eureka moment, the scientist is unlikely to assume this is immediate salvation - going forward there'll be two branches of humanity.
