I am doing data migration myself for 11 years now, especially with material. If your MM consultant is so smart to know that maintenance status are OK then why does he not know the solution?
Of course nobody enters the maintenance status manually when creating material, they do it indirectly by selecting the views in MM01.
In the BAPI it is a bit more up to the ABAPer (you) as you have to tell the system what you want do, which means you may have to submit some field contents that are invisible for a normal user (and MM consultant) and which are determined by SAP logic if you do it via the normal GUI transactions.
I know that this OSS note is very complex and it took me more than a day to understand the details, I even did brainstorming with my colleagues on that.
I think it is not serious if I tell do that or do this, as it might not work for your specific case, since I do not know your data in your system and I do not know what values you submit via the BAPI (except those 3 fields from above).
To get help in the details you would need to provide details.
a) VPSTA and PSTAT from the existing material from MARA, PSTAT from MARC and MBEW.
if course along with the key fields.
b) all segments and their fields that got values with your BAPI call.