Sing Out! has just published an article by Michael Cooney regarding the relationship between traditional songs and singers and Bob Dylan's compositional processes. You should check it out. It includes a good story about Woody Guthrie's advice to Dylan on this very matter. I can assure you that Woody did not urge him to scrupulously respect copyrights or the claims of traditional singers.There is always much to criticize about Dylan, but when all is said and done he has done more than just about any other person to enrich the folk tradition (broadly defined), it is hardly surprising that his work shows his traditional influences to those in the know.
As to Lorre Wyatt (who by the way is a man, not a woman, as some of the misspellings of his name suggest), he is a pretty good songwriter, and a very good singer of "folksongs," but he did not write "Blowing In the Wind." His best known song is probably his ecological rewrite of Elmore James' "Baby What You Want Me to Do?" which Pete Seeger an many a Clearwater crew member have sung over the years (Sailin' up/Sailin' Down/Sailin' up down/Down up/All along the River . . .).
What is true is that Lorre made one of the first recordings of "Blowing In the Wind" as part of a high school folksinging group that was an adjunct of the chorus at Millburn (N.J.) High School called the Millburnaires. Indeed, this may have been the very first recording of the song, limited edition L.P. that it was. This L.P. lists Lorre as the composer. He had heard Dylan sing it at some club in the village before he or anyone else really knew who Dylan was. He liked the song, taught it to the rest of the group, foolishly took the credit, and the rest is history . . .