Ofcourse it is possible to create an order for a customer through the backend, but afaik there is no way of changing the price, changing the product name (without changing the product).
Same as changing an existing order. I.e. Customer just ordered something and picks it up in the store. For Some reason we want to give her a â‚¬5 discount, can we manually change the total or give a discount? (Without the need for a discount code)
Sure you can do all this, except for changing the product name.
Seems that you are right, you can change the price of a product. However, manually adding a discount would be a better solution.
The part in Green is what you can change manually. The box in red is locked. What would be the technical issues here for this to be locked?