Yes and no.
Rapture can be a challenge. The RPro installer removes any Rapture wavs found in the RPro multisample folder. I guess some one thought there was no reason to have duplicates of the RPro flac files. Unfortunately this breaks some Rapture programs. Either do not merge the Rapture samples or keep a copy handy. They will be needed if the RPro installer is run again. It happened to me with every update. It is not a big deal but is a little inconvenient.
Merging DPro is not a problem. The lastest version DPro and RPRo both support flac files.
Since VST Persist Compatibility for RPro is not available, if you do merge the multisamples make sure to create the appropriate directory junctions or update the "Multisamples Folder" registry entries for the legacy synths and the RPro registry paths for the legacy folders.
Initially, you should not need to merge programs, RPro copies DPro and Rapture programs during the RPro install process. However, the legacy synths are hard coded to look in ProgramData for programs and some support files. This is unlikely to change because the synths are no longer maintained. Should you create a new program or modify a program using a legacy synth, these changes will not make it to RPro without either copying the files by hand or using directory junctions in ProgramData so that legacy programs actually work on the PPro file locations.