In 31.5kyr, Epsilon Eridani and Luyten 726-8 will be < 1ly close; but how distant from the Solar system?
These stars are currently moving away from us, in the case of Epsilon Eridani, at 15.5 km/s. In 31500 years they will be further away than they are now, the distance can be calculated by applying Pythagoras' theorem to the distances and velocities you mention.

It turns out that Eps Eri will be about 12.2 light years from Earth, and Lutyen 726-8 will be 12.6 light years.

They won't be particularly close together in the sky, I estimate about 3 degrees, and they will be even dimmer than they are now, though Eps Eri will still be a naked eye object.