For reference:
I don't think you need to worry much about which version of Elijah to use - you're going to want the new PoC2 version over the old promo. He can choose your blocker for you (which when banded into battle means that whoever was blocking before gets kicked out), and he's protected from discard and banish.
Choosing which Moses is a bit trickier, and it depends on how you're playing the deck and who you're playing Transfiguration from. There are three real possibilities:
These all have their own unique advantages and disadvantages. Old Mo has been a longtime staple. FBTN isn't the powerhouse it used to be, but it's still pretty decent, particularly when banded into battle. CoW has a very similar ability, but he has the added advantage of also being white brigade (in common with whoever was using Transfiguration) and the double-edged sword of his TC negate. This can be extremely powerful, but if you don't build your deck around it that negate can bite you just as hard as your opponent. PoC is a bit different - incredibly powerful when playing Exodus enhancements, and with the ability to create an even bigger band, but no negate and larger numbers (making it more difficult to actually play those Exodus enhancements). That said, most Exodus characters are white, meaning that a solid Exodus offense (which probably runs PoC Moses anyway) can be a solid option for the rest of the deck.
Transfig as a non-interrupting FBTN has historically been pretty popular, and both Old and CoW Moses will do that for you. It's slightly less good now that there are... four? different Scattered-like cards (AoE evil battlewinners that gain CBN against multiple heroes), but with the bonus numbers that Elijah now brings there's little that will win by the numbers versus a full Transfig. That said, if you do run it as a full Exodus offense (which may be pretty decent, seeing as it's a good mix of Transfiguration's white and Elijah's green), there may still be a consideration for running PoC so that you can play all those wonderful plagues CBN.