Actress Allusion: Bette Midler (voice of Georgette) currently has a New York City apartment at 1125 Fifth Avenue, so she has same address as her character and probably lived there when the movie was made (unless it's an astounding example of Life Imitates Art).
Channel Hop: In North America, this film has always been with Disney; however, in most international territories, it was originally released in theatres by Warner Bros., and in other international territories this was handled by United International Pictures. This is due to output deals Disney made for international theatrical distribution.
Dueling Movies: The 1980s were a very tumultuous time in animation. Don Bluth had very publicly split with Disney and started his own studio, which naturally was in competition with Disney. Oliver had two rivals from Bluth: The Land Before Time, which came out on the same day; and All Dogs Go to Heaven, released the following year but also featuring a roguish talking dog and a heartwarming little girl. Oliver did better than either in theaters (though "Time" had the higher opening weekend and worldwide gross), though it's now a somewhat forgotten member of the Disney canon while The Land Before Time and All Dogs Go To Heaven went on to spawn long-running video franchises.
What Could Have Been: Originally this movie was going to be a pseudo-sequel/spinoff of The Rescuers that followed Penny after she was adopted. You can still see some traces of it. (namely the main character's name being changed to "Jenny").
Oliver & Company is the final film in the Disney Animated Canon to go on to the Disney Vault after leaving theaters in 1989. The critical and financial success of The Little Mermaid the next year convinced Disney to immediately release that film on video in the Walt Disney Classics line and started the continuing trend of releasing canon films on video after theaters like most other movies. Oliver didn't return until the 1995 reissue on Disney's seven-year plan, and THEN it was released on video itself, in the Masterpiece Collection.
This also is the first film in the canon to have sound/music from the film's soundtrack appear over the Walt Disney Pictures Vanity Plate in place of the "When You Wish Upon a Star" excerpt, The next one to do this, The Lion King (which also has Cheech Marin), would not come until 1994.