Yes, the legacy versions of our apps can coexist with the new 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 you’re working with in one of the legacy versions of the apps, to the new apps, just long-press on the Case Folder in the legacy app and choose “Open In...” and then choose the corresponding new app icon. Here’s a support article on how to do that: https://support.litsoftware.com/hc/en-us/articles/360050394554-How-do-I-move-my-Case-Folder-from-the-legacy-app-to-the-new-app- (You have to be in the free trial period, or a subscriber, for this option to be available.)
Before doing this it's very important to make sure your Document Storage location is set to On My iPad by following these directions: https://support.litsoftware.com/hc/en-us/articles/360058332714-VIDEO-Changing-the-Document-Storage-Location