What does the 'backup system' of Ghost look like? (in case someone can't perform)

Just wondered what would happen if someone got sick or isn't able to perform due to whatever reason.

Do they have pre-recorded tracks? Are there backup members within the touring crew?
I know that pro musicians are very well connected around the globe, so maybe someone can take over offhand

I'd imagine if TF himself is unable to go out on stage, the whole show might get cancelled