A picture of Tom Paris in a cadet uniform is shown on Admiral Owen Paris' desk. It is actually a picture of Robert Duncan McNeill playing a different character in the Star Trek Universe: Nick Locarno from The First Duty (1992). Depending on which story you believe, either the Tom Paris character was originally meant to be Locarno but there were legal issues with "The First Duty"'s writers, or the Tom Paris character was developed separately and McNeill's casting was an afterthought when someone noticed the similarities between Locarno and Paris.
The holographic Tom Paris still has two pips on his collar, since Lt. Barclay is unaware of Tom's demotion.
Reginald Barclay makes his first "true" appearance in "Star Trek: Voyager." Although Dwight Schultz had played the character four years earlier in Projections (1995), it was only a hologram of Barclay.
In the Pathfinder holodeck, the holographic Torres shoots two (real) Starfleet security officers with a holographic phaser and it has no effect. This marks one of the very rare occasions that holodeck safety protocols are seen functioning correctly.
Barclay's holographic imagination of the main characters is based on how they looked before leaving the Alpha Quadrant in Caretaker (1995). Captain Janeway has her original hairstyle, and Chakotay and B'Elanna Torres are wearing Maquis fatigues rather than Starfleet uniforms. Neelix and Seven of Nine, who were added to the crew in the Delta Quadrant, do not appear in his visions, although the name of his cat indicates he is aware of them.