This is exactly what I needed. Thank you!
For anyone else that needs this here is how I found what I needed for my column names.
List<String> attributes = new List<string>();
// here you can access the fi.ItemsList collection which
// returns the list of all fields in the form of FormFieldInfos or FormCategoryInfos object.
List<CMS.FormEngine.FormItem> formItems = fi.ItemsList;
int attributesCategoryIndex = formItems.FindIndex(i => i.ToString() == "CMS.FormEngine.FormCategoryInfo");
CMS.FormEngine.FormCategoryInfo ci = (CMS.FormEngine.FormCategoryInfo)formItems[attributesCategoryIndex];
if (ci.CategoryName == "Attributes")
{
for (int i = attributesCategoryIndex + 1; i < formItems.Count; i++)
{
attributes.Add(formItems.ToString());
}
}