Brass, strings, percussion etc. instruments didn't cross your mind?
Oh, sure, sorry, I misinterpreted.
The post/discussion you were replying to was specifically about wind instruments, so I got confused
However, if you have much more than a quartet and a few wind players you have basically a small orchestra, which comes with a lot of financial and logistic problems (musicians take room on stage and have to eat and sleep somewhere ) and requires a big shift in thinking from the "band" mentality - for starters, you need to conduct them
It doesn't seem very feasible to me for more than a one-off date - nor, frankly, interesting: you'd be looking at a band stressed beyond reason, playing the album arrangements yet one more time, possibly with a under-rehearsed orchestra and bad acoustics.
I'd be more interested in seeing them touring with the kind of agile, versatile ensemble Loreena McKennit has used in the past - no more than 7-8 cleverly employed additional musicians who occasionally double on a second instrument.
I think the 2018 tour will be a preparation for the next album. I'm sure they are going to test some things and use that experience in studio. I've got the feeling they know they have to reinvent themselves or, otherwise, they are doomed to a slow death, so they get the urge to try new things and enhance their sphere of action: a string quartet, a wind section and more folk elements. Now they are in a position in which they can do whatever they want, they have reached a status which allows them to experiment and get away with it, and that's exciting. I'm sure the next album will be really special.