In that case I would say the same recursively to all of the different vendors and contractors involved, but that quickly becomes a much more complicated problem than someone just dumping the source online.
Yep, and it's massively complicated by the age of the software. Most of Ambrosia's catalog was released in the 90s -- most of the consulting groups involved have probably long since been acquired or dissolved, any contact information Ambrosia had for the developers is probably stale, and some of the developers may no longer even be alive to grant permission.
Additionally, some of the games distributed by Ambrosia were written partially or entirely by outside developers. It's not clear if Ambrosia even had the source to all of their games, let alone the rights to relicense it.