Sanctuary

Christopher Heyerdahl (Big Guy) is listed in the opening credits but does not appear in this episode.

Emilie Ullerup (Ashley Magnus) appears in some flashback "memories" prompted in her mother by Adam Worth's avatar. Although the majority of the shots are previously seen footage, the last image of Ashley dressed in white may have been new.

The title of this episode was also the title of a Season 7 episode of Stargate SG-1, Chimera. Damian Kindler, the creator of Sanctuary, wrote the teleplay for that episode.
As for the title tying in with this particular episode, the word Chimera has many meanings, several of which, given the Praxian "organic sentient tech" involved, might apply:
1. An imaginary monster compounded of incongruous parts.
2. A fanciful illusion or fabrication of the mind, especially an unrealizable dream.
3. An organism, organ, or body part consisting of tissues of diverse genetic constitution.

The original songs used to communicate with the Abnormal were composed by series creator Damian Kindler (who also wrote and directed the episode) and series composer Andrew Lockington.

The song that Gregory Magnus (Jim Byrnes) sings to his daughter, Helen (Amanda Tapping) is entitled "Of Whom Shall I Be Afraid". It is sung by Jim, who co-wrote it along with Steve Dawson.

Early in the episode, when the scene changes from Magnus and Will in the Sanctuary to Henry and Agent Crealy in the alleyway, there is a painted ad on the alley wall which momentarily displays the names of Sanctuary's three principal Executive producers : "Kindler - Tapping - Wood". Next to the names, in a big red circle, are the words "NICE BUNS!"

Although listed in the opening credits, Christopher Heyerdahl (John Druitt/Big Guy) does not appear in this episode. Conrad Coates (Monrovian Sanctuary Head) and Anjali Jay (Jasmine/Indian Sanctuary Head) appear only as participants in a conference video call. Jim Byrnes (Gregory Magnus) appears briefly as a figure of Magnus' imagination, singing her a song of advice.

The unexplained "With Special Thanks" end credit shout out to executive producer Keith Beedie continues.

For the third show in a row, the end credits contain, without explanation, a "With Special Thanks" shout out to executive producer Keith Beedie.

Although listed in the opening credits, Christopher Heyerdahl does not appear in this episode.

Series co-star Robin Dunne (Dr. Will Zimmerman) makes his directorial debut in this episode.

For the second show in a row, the end credits contain a "With Special Thanks" shout out to executive producer Keith Beedie.

The end credits contain a shout out to one of Sanctuary's executive producers : With Special Thanks to Keith Beedie.

Benoit: The only men I know are the ones who buy tickets to Comicon in San Diego - a year in advance.
Helen: A much better breed.

A shout out from Sanctuary to all their friends at Comicon, where Amanda Tapping and Robin Dunne are regular attendees - along with other Sanctuary cast and crew.

Jonesy: Miley Cyrus! That's gotta be against FAA regs!

When Magnus' jet mysteriously opens up with automatic machine gun fire at the two thugs looking to hijack it from the hanger, one thug exclaims with a strange reference to Miley Cyrus, the famous actress/pop singer.

Christopher Heyerdahl is listed in the opening credits but does not appear in this episode.

Robin Dunne and Ryan Robbins are listed in the opening credits but do not appear in this episode. Agam Darshi also does not appear.

Emilie Ullerup (Ashley Magnus) appears in flashback scenes.

Although listed in the opening credits, Ryan Robbins (Henry Foss) does not appear in this episode.

The episode closes with a poignant Armistice/Memorial Day dedication:

"Dedicated to all the men and women who serve in the armed forces.
Thank you for giving us Sanctuary."