I don't know what edition of Grimm's you are reading - there were/are many editions, and the brothers changed the stories throughout the publishing history of their collection.

We must remember that folklore is fluid and is not "set" until it is lifted from its natural oral environment and placed in print, where it is like a butterfly pinned to a drawer in the bureau of a collector - beautiful to look at, but no longer capable of flight. Folklore in its natural setting does not comply with the concept of "original."

I'm not an authority on the story of "Hansel and Gretel," tale type ATU 327A, but looking at the index provided by Aarne-Thompson-Uther, it is clear that it is a complex folktale with many variants and an entwined history. One should not be surprised to find various variants in print - and in the pre-print oral setting. I'm only seeing the name "Roland and May-bird" in an 1877 English translation of Grimm by Edgar Taylor titled "Grimm's Goblins" that rearranges only a few of the stories and may be altering them (but I have not conducted the research to be able to assert that in any definite sort of way). I notice that the title "Roland and May-bird" does not appear in the first edition of Grimm, nor does it appear in the standard, later edition of the comprehensively presented collection. Both have "Hansel and Gretel."

All that said, I would go back to my original point, which is that there is no "original" in folklore. Once we understand that to be the case, I'm not sure what question remains when the fog clears.

edited to provide name of 1877 edition and its translator.