There are several ways to approach this question, and a lot of the answers are good. However, I want to approach from a more directly harmonic area. As in the other answers, this issue is a desire to show function as clearly as possible.
Let's work through the keys you mention backwards:
C♭ major is entirely diatonic to the keys of G♭ and C♭ Major. That means that all three notes belong to the key. C♭ would be a IV chord in the first and a I chord in the second. Calling it B major—with all three notes completely foreign to the key—would be highly unusual, and would not even be a standard chromatic chord let alone diatonic. As such, there would have to be a very good reason for it: almost certainly a modulation to a distant key.
The only other place that C♭ major would be a diatonic chord is as V in the exceedingly rare key of F♭. This key—which would have to have B♭♭ in the key signature—is virtually never used, composers are vastly more likely to notate in the key of E. C♭ major is very unlikely in the key of E since all three notes are chromatic and it wouldn't have a clear chromatic function. Instead, composers would use B, which is the normal and completely diatonic V chord.
There are three standard chromatic functions that involve major triads: Modal Mixture (borrowing from a parallel mode), Neapolitan Sixths (major triad built on the lowered second scale degree), and applied dominants (borrowed "V" chords that apply to diatonic harmonies other than I). Those are the functions that will help us make guesses about the most common enharmonic spellings in the other keys you mention.
In D♭ and A♭ major, the most likely function of a chromatic C♭/B major chord is modal mixture. I say this because neither note could be the root of a Neapolitan (that's always flat 2, which would be E♭♭ or B♭♭ respectively) or of a standard applied dominant (neither spelling is a fifth above a diatonic note in those keys). In A♭, the chord would be a fairly common modal mixture chord called ♭III (the III chord of the parallel minor) and in D♭ it would be ♭VII (a somewhat less common chord in classical music, but it does happen, often as V/♭III). Since these chords are borrowed from the parallel minor key, they will be spelled as C♭ not B.
That covers your last bullet point and why they'd all be C♭. By a similar reasoning, I would disagree with your third bullet point about E♭. The chord on C♭/B is most likely to function as the modal mixture chord ♭VI borrowed from e♭ minor and so would still be most commonly spelled as C♭.
I agree with your second bullet point, it would still be C♭ in the key of B♭. Here, it's most likely function is as the Neapolitan harmony, often symbolized ♭II. Since that harmony is a major triad built on lowered 2 (not raised 1) it is far more likely to be a C♭ chord.
Finally we get to your first bullet point. The C♭/B major chord is (in common-practice classical harmony) VERY uncommon in the key of F. As a major chord from the opposite pole of the circle of fifths (a tritone away), it would be a highly destabilizing force in that key. It isn't a borrowing from the parallel key, nor can it be the Neapolitan, which is G♭. However, it also would not be any normal kind of applied dominant since neither C♭ not B is V of a diatonic chord in F. The closest, I guess, would be V of some sort of altered VII, which would call for a spelling of B, but ultimately the choice of spelling would be highly context-dependent. It would probably be used to set up a distant modulation, or as a snaky voice-leading chord. Whatever spelling is easiest to read in context is probably the way to go.
So, in the end, for the keys you discuss, C♭ is the more likely spelling of all except the key of F. Of course, I'm talking about common-practice here. I don't know as much about jazz or rock spellings.