Is there any way to modify what order different sections appear in the order details page in the mcp? I would like to more up the order notes section along with the product information section.

Also, the save and return button has been removed which was a really nice feature. Is there any way to get that back?

Unfortunately, there is no way to move the sections of the page that is built into the software.

Save and return is now irrelevant because when you edit each section they save individually. Save and return would indicate that the entire page would be saved at once.