Legal Question in Real Estate Law in California

Yes.

Sure they can. You don't get to avoid paying the guy who cleaned your carpets just because you got foreclosed, do you? HOA dues are for services rendered to the homeowners. You owe that just like any other debt and they have all the same debt collection options as any creditor.

Yes; HOA dues are a separate obligation from the mortgage and there is no protection under the anti-deficiency laws against a collection effort after you no longer own the property.

I agree they could go after the debt, but I wonder if the HOA fees are made under the homeowners CC&R's a first lien against the unit, whether that might effect the ability to collect once the security has been foreclosed on? I do not think they had the right to call your employer before any judgment had been granted as that seems to be improperly placing pressure on you to settle.