I don't. Just about any one of those things can be found to not apply in one version or another of the Batman mythos.
The 60's Batman never goes into the origin. We just accept that rich playboy Bruce Wayne is Batman. So, you can leave out the part about him seeing his parents killed, the training, why he chose a bat as a disguise, etc. Also, no Two-Face.
Heck, the original serials didn't have any recognizable villains in them. And Robin isn't really a "boy".
Silver-Age Batman (and some other versions, along with the background cameo of the original Batsuit) had Batman getting his inspiration of the Batman costume from a costume his father wore at a costume party years ago.
Alfred wasn't always the former-secret agent character he's become. He was originally just a portly butler to Wayne Manor.
Of course, all of this ignores the various elseworlds and alternate universe comics (and the handful of animated elseworlds tales). An interesting one to look at would be Just Imagine... Stan Lee's Batman.