It is normal to second guess yourself in this type of situation. If your lawyer is confident, you should be confident too. I have no experience but form a general standpoint it seems that you have a strong case; you even have statements from his family.
Try to remain calm. I'm sure everything will work out for you.
In may case I visited 4 attorneys before I decided to go on my own, all of them have told me to send few proofs of bonafide marriage like a couple of bank statements, few bills, 2 affidavis and a short testimony of myself one of them told me please do not write more than 3 pages so we do not overwhelm them with so much evidence and few pictures.
I finally did my own package and put as much evidence I found, I used a thick 4" binder, I included all the same evidence I mailed the first time when I applied for I-130,shipping labels from online purchases with my name and my spouse name, invoices under my name or my spouse name, all the bank statements for the last 3 years, pictures as collage like 15 pages. My own testimony with all details from how I met my spouse how the relationship was developed and how the problems began, it took me 10 full pages wrote on World on Arial 11pt. I did not have any police report or court order, just 3 affidavits with testimonies of spouse aggression, pictures of injuries done by my spouse to me, receipts from visits to my psychologist, and pictures of the meds I am taking for depression and letter from my therapist.
It looks like you have a strong case, looks like you should get a "Establishment of prima facie" letter soon.
Wait 10 days counting on the day you sent the package and call your attorney to see if they have receive any "Receipt Notice" and after that 20 more days to see if they receive any other notice like "Establishment of prima facie" or "RFE".
In my personal opinion if you receive any RFE....do it yourself, I figure that the lawyers are trying to a light work so they can charge more money to people later to reply to a RFE.
It seems you submitted enough proof ob abuse, if USCIS needs more proof of a bonafide marriage they will issue an RFE and you will have time enough to gather more documents .
I advise you to attend therapy for your own sake and your children as well. When children witness and/or suffer abuse the chance of them growing up dysfunction is very high.
