- If PL5 and PL6 can coexist in the same computer.
Yes. You can also install PL6 as a free trial to check out if it works for you (and if that answers your other question).
-If one can use View Point 3 in PL6 or if one has to upgrade to version 4.
Asked here and it looks like it would work.
- If Deep Prime XD recognizes Fuji’s X-Trans files, if not whether a future support is scheduled.
Not yet (only Deep Prime is supported), but support is planned for a minor 6.x release.
- If the new camera/lens profiles will continue to be incorporated in PL5 or will they only be available in PL6?
No idea. Looking at Appareils supportés - DxO it looks like camera models require a new version of the software (e.g. support for the Fujifilm X-H2S was in PhotoLab 5.4), but camera+lens profiles for optical correction are downloaded as modules from the DxO servers and might be backwards compatible? I’m seeing a lot of profiles marked as compatible with PhotoLab 5.0 (even if the module was created after PL 5.1+ was released). I don’t know if DxO changed their module format between PL5 and PL6, or if they might restrict access to new profiles to PL6 users for commercial reasons. Maybe someone else knows what the usual practice for that is.