But if the case is dismissed, the creditors will get no benefit from this asset.

The poster did not mention a dismissal.

The Trustee might object to the discharge, but that is unlikely. The case will be open until the PI case is resolved and the creditors paid from the net proceeds. Debtor amendments apply back to the time of filing. If the case was closed and debtor now tries to reopen that is a problem.

I have represented Trustees who have objected to, or moved to revoke, the discharge of debtors who intentionally omit significant assets, especially when it appears intentional. It is a huge problem when the defendants in the PI case can raise judicial estoppel as a defense, and we have had to settle for less than a case is worth. We have referred a couple to the US Attorney. Yes, it happens.