The laminate looks mostly dry after a leak. Does the contractor need to check underneath it?

Yes. The visible surface is only one part of the floor. EPA's clean-water guidance says the subfloor beneath flooring must also be cleaned and dried. Ask how the contractor will assess the underlayment, slab or wood subfloor and whether lifting affected flooring is needed for access. The answer depends on construction, damage and contamination; a dry-looking surface or a rug covering a buckle is not evidence that the layers below are ready for repair.