The Memory Alpha page for this episode has the following to say:
Since no date or stardate is given in the episode, the only element that dates the events is Seven of Nine, placing this episode sometime after "The Gift". These events take place at least 700 years after Voyager encountered the Kyrians, placing the activation of the EMH backup and subsequent upheavals in the late 31st century (approximately 3074). The final scene, however, takes place no sooner than seven years later, although the docent's monologue, and Quarren's statement that "it could be another seven hundred years," both imply that several generations have passed. It is reasonable to conclude that the final scene takes place as early as the final years of the 31st century, and as late as the 38th century. Chronologically, this scene probably takes place farther in the future than any other filmed scene in the entire Star Trek franchise.
So, considering that the events of 'Shockwave' are placed in the 31st century, it is very likely that the last scene, at least, of 'Living Witness' was set after those seen in 'Shockwave'.