What can I do if my wife abused me and our US born children who are in my custody?

I'm Canadian, entered US by land 2000, no visa required- thus 12y overstay by now. My wife (we were married in E. Europe 2000) was granted Political Asylum on US soil 2002; but hasn't mentioned me to immigration, or the fact she was married. We lived together in US 2000-2003, and had daughter 2001 and son 2002. Wife was found "indicated" by ACS for neglect/abuse in 2002 and 2003. Also, in 2003 she had me arrested twice on DV, later dismissed. Her third crazy 911 call in 2003 led to her arrest instead. I co-operated with DA office, and wife pleaded guilty to Assault3/harassment in exchange for being under outpatient jurisdiction of Mental Health Court for 13months, during which I was granted full order of protection. Then her case was sealed. In 2004, ACS agreed in neglect hearings to discharge children from foster care to me under supervision; wife only came to first neglect hearing, didn't show up for next six and got outright dismissal! In 2005, same court gave me final order of custody on default. In 2006, OCSE served my wife in NY; instead of appearing 2mo later, she called Support Court and testified under oath that "calling from the old country, banned from US for 10y"-thus fraudulently winning dismissal. She never left US and likely became LPR 2007 and USC 2012... So: 1) May I obtain certification for U-visa, based on successful prosecution of crime in 2003? 2) May I file VAWA, having no hard proof of her status and whether she might have divorced me anywhere worldwide? 3) Does child serious med/psych allows to expedite parent's VAWA(if VAWA is based on parent abuse, or on child abuse)? 4) In addition to police clearance, do certificates of disposition with seal re: my arrests clear me completely? 5) How can "entire ACS case file" help?