No, they don't all need to match.
Yes, they should match in the line of sight (so you don't doors in the same hallway that are different from others).
If they will bother you, just replace them. Especially if the old doors look crappy.
It would have been awesome to replace all of our doors post-renovation to be the same, but that also would have cost another $4-$5k; which just wasn't justifiable at the end of the project. The old doors were nice, we just changed the panel design on the new doors. I'm sure I'll regret it, but we need to draw the line somewhere on this project that has experienced significant "requirements creep."