Yes, the legacy versions of our apps can coexist with the new LIT SUITE apps as separate apps on the same iPad. They won't be changed or updated if you install the LIT SUITE, and they can still be used.
If you want to transfer a Case Folder from one of the legacy apps, to make it into a Case File in one of the new LIT SUITE apps, just long-press on the Case Folder in the legacy app and choose “Open In...” and then choose the corresponding new LIT SUITE app icon.