At O just the first two of your options apply initially.
If he doesn’t get an interview, he’ll be told by email and his application will be over.
Or he could get an interview invitation to his original college, or find that he has been shifted to another one. Some subjects will do interviews at more than one college as standard. Some might call them for another interview at a pooled college after the first round, which will happen in the week or so following the first interview (this is why O candidates sometimes used to spend 2/3 days there, waiting to see if some one else wanted to see them). Then everyone who made it to interview finds out on the same day in Jan.
Sonoption 3 only happens if option 2 did and is really just part of #2, and #4 doesn’t happen.
not sure that makes it much clearer :-)