I am a huge fan of Tad Williams. Although I loved Tolkien for many years, I had pretty much stopped reading modern fantasy, since so much of it was awful derivative stuff. Then I tried Tad's DRAGONBONE CHAIR, and sat up and said to myself, "Yes! This genre can be terrific, in the hands of a good writer."
I would likely never have written A SONG OF ICE AND FIRE without that inspiration.
So, yes, "Josua and Elyas" are definitely a tip o' the hat to one of my favorite fantasy writers. And here's a hint... there are numerous similar homages to other favorites buried in the text, if you can find 'em.