It seems that like Looney Tunes, Mickey appears to be a living toon who comes
out of the production cel (from Mickey's Birthday Party), even
walking around in a same studio and interacting alongside past selves (
that also happened in 1968 and
Mickey Mania/Mickey's Wild Adventure). According to a interview (
found the source, though some posts' Streamable/Gfycat links are no longer valid), it was said that he can
perform his cartoony acts outside the films and
is revealed to be
an actor (one for
Film Pictorial's September 30, 1933 issue claimed he and Minnie are married outside their public careers).
This goes further with House of Mouse showing the original short catalog
from 1930's to 1950's (besides that duel with Jafar; though former and next's feats only applies to his gang and Pete, not potentially other verses). Then, there's that recent anniversary short "Steamboat Silly" which acted as the finale to a 2013 cartoon, literally ending with concrete proof about multiple medias such as shorts themselves, films (Fantasia and Fun & Fancy Tree) and many others (Nash Ambassador commercials) as Mickey accidentally released them from the film reels across his history, like a now-PD incarnation had earlier.
Since DimeUhDozen brought up Goof Troop, Max did make an appearance in House of Mouse and those direct-to-video Christmas films as a grown-up, besides Mickey and Donald having their brief moment in a sequel movie (Pete was one of the main characters in a show itself; ironically, they didn't age up that much compared to former).
As said before, some of the media like Clubhouse-like cartoons (
despite latter's small references like a plane; even Kingdom Hearts thus far) and comics (especially Italian ones and Barks/Rosa's Donald Duck universe) are better as separate canons for now, though
a original 1930 strip (which even adapted Plane Crazy) was handled by Walt Disney and Ub Iwerks at first before
Floyd Gottfredson continued it. Unless there are indeed others that were implied to be connected with the films.
However, as we learned from our attempt to connect DC's tie-in comic with the original Powerpuff Girls, perhaps it'll be better for letting it up to wiki staff to decide what we can really use for the canon with a planned CRT above. Especially since we're talking about one of the most famous cartoon characters right here, it'll get quite debatable (
LT went by a little easily).