I am so sorry that you and your children had to go through this today. It must have been terrifying.
You've gotten some good advice here, except perhaps the gun. With someone who is mentally unstable and a substance abuser, it is more likely that he would use the gun against you.
The call to the lawyer was an important move on your part and she/he can give you advice and take steps to protect you and your children. Probably the best thing to do is to get child services involved with supervised visits where you are not involved and if your ex ever has alcohol on his breath the visit will be canceled.
Hard that your sponsor is away right now; right now your daughters need you sober more than ever and so do you.
(((Hugs)))
I also like the idea of contacting a domestic violence group; your ex threatened you and your children and some statements you made show that you are very much afraid of him and that he can still force you to do things against your will. I wish you had called his bluff with him ripping his shirt and threatening to scratch himself as if you had done it...your fingernails would have been clean, but not his.