Missouri is one of the states that has an online query tool re: state/county court cases. Michael J Avenatti is the only Avenatti that shows up in a search. Traffic violations and a small claims suit so nothing huge. So, while the parents are still a bit of a mystery, at least we have some verification that his high school years spent in Chesterfield MO / Parkway Central High appears to be legit.

https://www.courts.mo.gov/casenet/base/welcome.do