What entitlements does she have(wife) and what do I have as far as stuff we own together new cars ..pension ,social security

If the Divorce has not been finalized it may have been dismissed. Check with the Court and he should file for Divorce not legal separation.

How should I proceed considering the situation described below?

He is vulnerable & you should proceed in all ways including divorce.

Wife demanded new car as condition of marriage now wants divorce. Do I have grounds for annulment or other financial protection?

I agree with all 3 of the answers. It should be a pretty easy divorce.

My ex-wife is threatening me if I don't help her financially she's going to go to court and file motion to Quash she had no

If she is correct that you fraudulently signed her name to all the Divorce documents she can go in and get lots of relief.

Now that your former husband is dead you can remarry your current husband.

You need to file an RFO to enforce the Judgment and /or a Contempt.

Can I file contempt charges?

You need to file for exparte relief asap to have the court order him to give you back the car adn car keys. you can also file an RFO for support.

Can my husband sue me for alimony and get other marital rewards later although he committed bigamy?

California is a no fault state so his Bigamy won't effect the Divorce or your options in anyway. You should check the Courts case summary to see...

Can i get custody if the mother let me take my child so she can have a life then decided she wants to take care of him

Yes you absolutlely can and should. You need to file a Parentage/Custody case.

Can my husband make me sell my house in a divorce ?

And also not if you don't agree and he does't get a Court Order requiring it to be sold. The Courts generally wont order that until the end of...