Question: We witness the closure of the tesseract once Coop successfully sends the singularity data back to Murph. And then it appears that Coop is sent back through the wormhole to our home galaxy.

Is the implication that the wormhole remained open, and only the tesseract was closed?

If so, then I imagine as soon as Coop rendezvouses with Brand, the rest of humanity will follow (at least the ones who don't prefer living on a giant cylindrical habitat)? At any rate, it doesn't seem likely that Dr. Brand would be alone for very long, which takes some of the urgency away from Coop's final voyage.

Answer: 
No. The wormhole is closed according to Christopher Nolan, the director:

<http://www.ign.com/articles/2014/11/08/jonathan-nolan-interstellar-spoilers>

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> Nolan: ... By the end of Cooper's journey, the wormhole is gone. It's up to us now to undertake the massive journey of spreading out across the face of our galaxy. Brand is still somewhere out there on the far side of the wormhole. The wormhole has disappeared entirely. It's gone.
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> IGN: And he has to try and get to Brand in this little ship?
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> Nolan: That's the idea.
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This, however is confusing, even though the director said it himself. The movie implies that the worm hole is open and that Cooper is going to travel back through the worm hole and reunite with Brand.

If the worm hole was gone, then how would Cooper ever possibly find Brand? She is in a completely different galaxy that would take thousands? millions? of years to reach by ship without the worm hole. If that is the case, then where is Cooper going in that little 1-man ship? What is the intent? It doesn't really make sense in the context of what you see at the end of the film. The movie certainly implies that Cooper and TARS steal the ship to fly back through the wormhole and reunite with Brand. This is the only interview I've seen where Nolan has explicitly stated this.
Depends on where Cooper Station is, which I think doesn't matter.

After returning from the first planet (Miller's planet, with the sunamis and the crazy time dilation), Coop and Brand are the same age and Murph is 23 years older (Murph is at least as old as Coop was when he left) and Romilly has gone gray waiting for them on the Endurance.

Coop and Brand stay on the same time scale relative to each other, up until the moment that they are slingshotting around Gargantua and Coop ditches Brand so that she can make it to the third planet (Edmund's planet). The closer you are to Gargantua the more extreme the time dilation. So, as Coop falls closer to the black hole, he would experience time ever slower and slower than Brand (and both of them much slower than Earth); but on the other hand Coop was only falling for like a few minutes (from his perspective) before he enters the tesseract. So it's hard to tell how much difference there is between Coop and Brand as they are both very near Gargantua but Coop was that much closer for a few minutes.

Then Coop is in the tesseract. Although gravity leaks through the tesseract back in time, Coop cannot go back in time (otherwise, he could have just told Murph what to do in person instead of having to manipulate gravity waves; for that matter, "they" could have gone back in time their damn selves, or at least sent Morse Code themselves, instead of taking the stupidly big risk that is the movie). So, I'm guessing when you emerge from the tesseract, you have not gone back in time. (You may have not moved forward in time either; at any rate Coop was only in there for a few minutes so no big loss).

After the tesseract, Coop awakens on Cooper Station (the ring habitat), and Murph is dyingly old. So like another 70 years have passed for Murph (she's like 100), and just days for Coop (since the mission started), and perhaps days or weeks for Brand. Remember also that Earth only had a few more years of life left, which means that Cooper Station was launched very shortly after the adult Murph worked out the calculations, which means that Murph grew old while living on Cooper Station, as no one was living on Earth.

All three planets on the Gargantua side of the wormhole experience significant time dilation relative to Earth (remember even Dr. Mann was marooned on his planet for so long that he lost hope and went crazy). So if Cooper Station left Earth like 70 years ago (or before Earth died anyway), it's possible that all those years did in fact pass (for Murph) in the few minutes that Coop and Brand were slingshotting around Gargantua's event horizon. Maybe Cooper Station emerges from the wormhole around the time that Coop and Brand have completed their slingshot. (Also assuming Murph's gravity calculations also allow rapid flight from Earth to the wormhole near Saturn; it will take NASA Cassini Space Probe 20 years before it gets to Saturn in 2017). So end result: Murph is old, Coop wakes up from the tesseract, and maybe Brand is roughly the same time scale as Coop. Coop picks up Brand at nearby Edmund's Planet. No need for wormhole--could be closed, could be open. Nobody knows.

On the other hand, if Cooper Station is on this side of the wormhole then same diff. Murph is still crazy old, but Coop could not get to Brand except through the wormhole, which must still be open. Again nobody knows.