Default Max Qty Level is used for the quantity from which the discount will start. Like if you set default max qty level to 5, Any rule below that quantity will be excluded either it has been set to global level or product level.
What type of product add-on you have configured? It should show on email. Can you please share some screenshots of your configurations and emails so that I can get a clear view?
Actually, It will happen with some payment gateways because some payment gateways are immediately changed the order status on order creation. of ex. BACS gateway will change the order status to On-Hold.
So here is the solution. In Order Custom Statuses Module there is 1 option Set Default Order Status Forcefully. Please try to enable this option. It should be work for you.
Actually, Wocommrece API will not help you here while creating an order with meta. By the way, Booster is saving all the fields as order meta. But in Woocommerce API, They will only allow to update the meta values and not create new meta values.
Did you try once saving the product once in which you have inserted meta values from SQL?
Sometimes it may solve the issue. So please give a try.
If not worked create a support ticket.
Actually, You can definitely use a booster add-on for sequential order numbering. Once you define the last order ID which is currently there the sequencing process will start from that. Regarding prefix, if you enable any prefix it will also be added to old numbers.
