No. JMS, when commenting on the million years in B5, discusses the Minbari and Humans as separate species still. Though we don't know - if we assume the descendants of Sheridan and Delenn are human, it will make a hybrid population of humans just as the Minbari (but not all) already are a hybrid population from Valen.
Also it is almost certain that Catherine Saki went back to Valen but unknown if she also transformed. We do know the pure Minbari were offended by Valen's descendants and they went into hiding. And it is virtually impossible they knew Valen's true nature so it must be because of his wife.
There also could be a third population from further Minbari/Human hybrids now that Valen and Delenn made it possible, but that would be entirely speculative.
Did the future humans leave the galaxy as the Vorlons did?
"No point in leaving the galaxy; stars go nova, it only affects the immediate vicinity (big as that is). By this point, they were in the position of the Vorlons, and now have to take their (our) place guiding the younger races, the next wave, while not getting in the way and remembering the lesson of the shadow/vorlon conflict."
What about the other races?
"The Minbari eventually make it; the Narn and Centauri do not. They don't die out, they just don't hit a state of First One-ishness, which is darn close to"