Well, I am not sure if I will be able to explain easily the challenge, but I will try to make this topic the most clean possible.
One thing that I feel that CS Cart Multivendor is missing is a feature to restrict which order status a vendor can choose. In my opinion this should be a default feature, but our happiness there are two addons that do something similar (links in the end of the topic).
But there is a problem with both addons, and a few others I've seen before, which is the "incomplete" status. I am not sure why, but no addon that I saw seems to be able to hide the "incomplete" status for vendors or restrict it someone way. Is like if that any code developed for orders status doesnt work with the incomplete status.
So here is my doubt how is possible to hide the incomplete order status from the dropdown menu in order management page?
Vendor restrictions: https://marketplace.cs-cart.com/vendor-restrictions.html
Order Status Restrictions: https://marketplace.cs-cart.com/order-status-restrictions.html