This post is so my style of thought topic, I almost it was a very old post I may of done but no!

As for Orla it could be a possibility that she had True Colour's as a solo. As for You'll Be in My Heart I just can't see it, that song to me was made for Alex, it requires to me someone with a certain expressive performance, and in honesty it neither would it work at it's very best with Lisa K either.
I would presume that Orla would had at least one older song on the set list because Lisa K herself had "The Voice" and Dulaman for Meav.
As for Meav it's a different story completely. She'd continue to reign Dulaman Queen, and My Lagan Love which there is a cover of her doing it on YouTube. Caranua to me was always a Lynn Hilary song. It was on her solo album just around before she first joined CW. Is it to say it wouldn't or couldn't be no. Now here's a more bigger question. Did they test the idea of Danny Boy in a group song because of now Meav not no more in the group and it being a signature solo of her too drastic for Lynn to carry her on herself? It probably wouldn't been different.
One if the significant unchanged songs would been Pie Jesu be performed by Chloe and Meav
Goodnight My Angel with Meav as well.
It's possibly Susan would sang "Faith Song" and another one would or may be "From The Distance" that she sang performed on "The Homecoming Tour" just before she left to have her baby. Now Eabha had a special unique song as well during that tour and she didn't depart, but this never made it on a recording and wasn't featured as one of her other solos on Ancient Land, so because of that key element doesn't mean From a Distance would make it either. Celtic Woman has a history of tour only exclusive songs whether a solo or group song and perhaps some of these are Tour test sampling's (Isle of Hope, Homecoming, Emerald) etc.
Would Susan done Shenandoah, why not. Faith Song, sure could it's near reminiscent to Sometimes a Prayer Will Do.
In conclusion Megan took Susan's spot similarly
Lynn replaced Meav identically
Alex did not replace Orla but carried the missing space to fulfill an Alto.