Are 401k catchup contributions taken into account in the cross-tested calculations?

In what sense? Certainly not in any current sense. However, since the IRS has seen fit to decide that it is impossible for recordkeepers to keep track of these funds separately, they count in the account balance for purposes of determining whether a plan is top-heavy in a subsequent year. In the absence of the IRS reversing this position, I would imagine that those amounts would count in any ABT done in a future year that used those amounts; i.e., in any test using the accrued to date method.

But I suspect that the answer you are seeking deals with the current year and hence the answer is no, they aren't taken into account.