Yes, they can. But I didn't realize that the particular batch of samples I linked to are in 32 bit float format, which RB 2009.5 can't read. It's pretty simple to use Audacity to convert them to 16 bit PCM, which RB can handle:
  1. Launch Audacity.
  2. Open the folder with the samples that need to be converted.
  3. Select all the .wav files in the folder. The easiest way is to use the Ctrl+A keys.
  4. Drag and drop the group of files into Audacity. This will open each file on an separate track. Note they show up as "32-bit float".
  5. Choose File|Export Multiple... from the menu.
  6. In the Export Multiple dialog, choose:
    • Export Format: WAV (Microsoft) signed 16 bit PCM
    • Export Location: Where you want the files to go. You can select the original directory, if you want to overwrite the original files. However, I believe it will "helpfully" create backup copies with the label "old" appended to the name.
    • Split files based on: Tracks
    • Check Overwrite Existing Files
  7. Click the Export button, and click OK at each prompt - once for each file, and a final confirmation dialog.
  8. Close Audacity.
  9. Select No at the Save Changes? dialog.
The .wav files can now be imported into RB. Note that multiple audio files can be inserted into a singe audio track:
  1. Select the track you want the audio to appear on.
  2. By default, RB tracks are in MIDI. Change the track to Audio:
    • Left click on the track to get the context menu.
    • Select Track Type: MIDI > Audio - Stereo from the top of the menu.
  3. Click on the track to set the point where you want the audio to be placed.
  4. Choose Audio | Import Wave File... from the menu (or press Ctrl+F3) to get the Open File dialog.
  5. Navigate to the file you want to insert. Select the file and press OK.
Although RB will place the audio onto the track, you probably will need to shift it around a bit to get it exactly in place. You can do this by selecting the portion of audio that needs to be moved, holding down the Ctrl key, and dragging it left or right. Release the mouse where you want the audio to be repositioned, and click OK at the Drag/Drop Edit dialog. Cut and Paste also work as expected.

I hope this helps!

-- David Cuny
My virtual singer development blog

Vocal control, you say. Never heard of it. Is that some kind of ProTools thing?