What they really need is an orchestra, Score was ammmaaazing, and IT needs one.
When they do the live DVD (that i'm assuming they will do, as there's only 3 albums in their whole catalog without an officially released one), I'm sure they'll have an orchestra, but i doubt for a full tour or even for just one leg.
I don't think they need a choir. I don't know why they don't just have JP sing the backup live instead of using a backing track.
This is the issue, probably JP cannot sing, or better can sing only to a quite limited extent.
In my view, technically speaking, a choir would do for a good part of their setlist, including many recent songs. I don't mess with financial speculacation of what they can afford or not, I only know there are hundreds of musicians around the world touring with choir with significant less average budget per concert vs DT. This is a fact. I don't need to make names, just think about recent concerts eg in your home town, wherever you leave and whoever was playing, and you'll probably have the evidence, think about all these mid-budget show productions...
Going back to the choir, it would be an added value if it would include male and female singers, leveraging poor John from being the big pretender in 90% of cases...
I see you have all different views than mine, still I think this would be a wise move, also because in the long run this would be a clever support to JLB... and would be a huge added value if they select the right people (like PF did at the time).