No one can guarantee that someone will get full custody. Write everything down. Document, document.
good luck!

sounds like a pretty big deal that the court should respond to, but the court system can be illogical.

The best thing you can do is prepare for tomorrow. Take notes, get everything organized. When did each incident happen? When your DH speaks to the judge report the most recent and serious things first and so on. How did you know about the house robbery? can you bring any documentation with you about it, such as a police report? why was the mother robbing a house? does she have a substance abuse or mental health problem? Do you have concerns about those issues? If so be sure to mention it to the judge and explain why you're concerned.

How is all of this impacting the child? Is she doing poorly in school? Emotional problems? you mentioned the boyfriend and lack of supervision with him, that's important to mention.

Dress professionally to court. Dress pants, ironed shirt, etc. This helps. If you don't have a lawyer you may want to get one. There are often free or reduced legal services available.

You as the stepmother, should not speak in court unless directly asked something by the judge. You can help your Dh but do it behind the scene. Your DH should speak to the judge.

The fact that BM took the child with her to rob a house MIGHT help your case, but you have to have documented proof - like a police report, and even then it is still not a slam dunk.

All the other stuff you listed will not get you custody.

For custody to change there has to be a significant change in circumstances. i.e. child's grades are poor, if the BM deliberately interferes with father's parenting time, etc.

Read this article - http://herstontennesseefamilylaw.com/2012/02/16/no-material-change-of-ci...

notice it keeps saying over and over -"there is no evidence that mother's action had a negative impact on child." You have to show how mother's actions directly affect the child - poor grades, having to go to therapy, etc.