You can read about the Michigan best interest factors here. Those are the factors the court would consider in evaluating your petition. There's no hard-and-fast way of knowing what a court will do - it's a case-by-case analysis.

If you make the petition and your ex- doesn't either appear in court or file any legal documents for the court, with his limited contact, you would seem to be a good candidate to get the name change. If you are soon getting married, though, unless you don't plan to take your new husband's name, wouldn't it make sense to wait until you are married so that you and your child have the same surname?