I know you said “without a complete wipe,” but that's honestly the best approach. Drag all documents and files to an external drive, take note of all programs your wife still wants on the computer, then clean install the OS. After, drag all files back from the external drive and reinstall all programs you made note of. That guarantees a clean slate.

Otherwise, you’ll have to go through the OS and attempt to uninstall anything that appears to be installed by the law firm, but usually you’ll leave behind small trace files and things that might keep them up and running.