The Danza: Christina Ross is played by Christina Moore.
The rare last name variety- Molly Shannon as Col. Beverly Shannon.
Dawson Casting: Averted, with everybody playing more or less their ages (including 20-year-old Debby Ryan, which is what makes this particularly notable for the Disney Channel).
Played straight in that Karan Brar is older than Cameron Boyce (albeit by five months).
Directed by Cast Member: Kevin Chamberlin directed "Are You Cooler Than a 5th Grader?" and "Say Yes to the Messy Dress".
Debby Ryan herself actually helped co-create the series: she's officially an (uncredited) creative consultant for the first season, a credited "Co-Producer" for the second season and is contractually entitled to become an executive producer for the third season. It's quite possible she may end up actually directing an episode.
Missing Episode: After "The Whining" aired, a nanny in New York did kill 2 of her kids like the Ross children thought Jessie wanted to do. Disney has since pulled all reruns of the episode and also removed from all paid download sites.
The episode "Quitting Cold Koala" was actually pulled just prior to airing and was retooled before its actual premiere after several parents (who viewed the episode in advance through Netflix and Disney Channel's own streaming service) complained about the episode's treatment of gluten allergies.
Katherine McNamara guest stars in "Kids Don't Wanna Be Shunned" as Bryn, a cruel Alpha Bitch type. This is her third appearance in such a role. (The previous two were in Girl vs. Monster and Kickin' It. Curiously enough, both those times she portrays a rival to Olivia Holt's character.)
What Could Have Been: Early promotional pictures for the series still shows Debby with her natural, "Bailey"-esque hair style. There are also hints that Jessie's surname was originally O'Keefe.
Emma was originally named Anabel. She was renamed in honor of Debby's Real Life best friend.
Luke was originally a Korean named Hiro.
Ravi was originally a South American named Javier. Mr(s). Kipling was a capybara. A lot of early interviews and promotional material still refer to Mr(s). Kipling (then yet unnamed) as a capybara.
Mr(s). Kipling was then going to be a Komodo dragon - this was after the name Mr. Kipling and the "actor" (Frank the water monitor, who does indeed play Mr[s]. Kipling on the show) were already frozen. Someone discovered that there were too many differences between a Komodo dragon and a water monitor to be believable (particularly the size), so it was changed to Frank's actual species.
Christina was originally named Pandora. She was planned to be a photographer.