Legal Question in Civil Litigation in California

Not unless you have obtained a default.

No, but if there was a violation of court order, you may request sanctions... this, of course, doesn't mean you will get them, but it is worth making a request at the OSC.

You don't ask for sanctions.

If you timely requested entry of default, and the court clerk entered his default, then the court clerk would reject his answer and you would have a copy of a rejected answer.

If you never requested entry of default, then the clerk must accept his answer. At that point, you must decide whether to move to strike his answer as being untimely filed. Some judges will strike and direct the court clerk to enter a default, others will overlook it as a simple procedural error.

I don't know any judge who will strike an answer and order a default entered unless there is clear and convincing evidence that the default was intentional, and the defendant is then just trying to back out of a clear decision to allow a default to be taken. The standards for overturning a default are SO minimal, that no judge is going to waste the time and resources of striking an answer, entering a default, and then having to either set it aside or be overturned by the court of appeals.

I know a couple of judges who grant motions to strike. One does it himself, especially after he sustains a demurrer with leave to amend and the party that has to file the amended complaint is late. The other judge that used to do it shot himself.