Complex restoring never works well when the first implementation is under the pressure of the real event. Other SaaS providers will be cursing such a big name tool making such a public mess.
DR is not a luxury. Systems that don't properly do DR aren't unoptimized or something, they're badly engineered.
It's more than a cliché that without restore tests, you don't really have a backup-- if the customer won't commit to testing the DR, we won't provide the service anymore. Anyone who pretends anything else is acceptable is kidding themselves.
Those all look like more trouble than they're worth before you start, but they aren't that hard. And you'll recover your whole investment the first time you need to restore something and it's just a simple tweak to your standard test practice.
If they had done this exercise even once a year, they would have known better what to expect, or how much it would take.