"Seems like a version of Edward to me. Don't see the two Brothers connection. Anyone?"

That's really interesting. First: thanks, Richie for drawing to my attention a version of Child 13 from my part of England, that I'd missed up to now. And associated with a Mummers' play, too!

Second, I agree that it looks much more like Child 13.

It seems to me that the essential characteristics of 'Twa Brothers', as defined by Child's seven texts (all Scottish with the exception of G, from New England) are:

(a) The two brothers are going to school.
(b) One stabs the other, in the course of a wrestling match.
(c) Attempts are made to wipe away the bloodstains.
(d) The dead brother is buried.
(e) Formulaic stanzas describe the excuses for the deceased's non-appearance, based on his absence in foreign lands, that will be offered to his relatives.

To these essentails is added (49B,C) a coda in which the dead brother's sweetheart charms him from his grave by musical means, and a verse or two properly belonging to The Unquiet Grave are appended.

In 49 D, E, F & G, the burial is followed by several 'What's That Blood?' verses, and the 'When Will You Return?' sequence (usually answered by reference to some unlikely antics on the part of the sun and moon) that are usually associated with #13.

The interesting thing is to look at the forty versions in Bronson, mostly from Appalachia. Just about all of them include the walk to school, the wrestling match, attempts to staunch the bleeding, and the burial arrangements. Several (e.g. #10, from Sharp MSS, Virginia) add the 'Unquiet Grave' stanzas, while a different Virigina version has the girlfriend raise the corpse by playing the banjo!

Only one of the 40 ends with the 'What's That Blood?' verses, and that's a version from Vermont (clearly of recent Scottish origin) in the Flanders collection, which Bronson called 'Edward Ballad'. It looks like a stich-up of 13 and 49.

All of which would suggest to me that the 'What's That Blood' verses are interpolations to the 'Two Brothers', effected back in Scotland at some point after the mass emigration of Scottish Lowlanders, first to Ulster and then to Appalachia, where they formed the 'Scoth-Irish' diaspora. The addition of the 'Unquiet Grave' verses looks like a separate and possibly earlier interpolation.

There's a bigger overlap between 'Edward' and 'Lizzie Wan' (#51), of course.