My customer needs to show different prices for products based on who logged in. Different customers have different prices for the same item.
And also, after the customer has completed an order, can shopify just send a csv or an email to the shop owner without the customer going through a payment process? Payment will take place after the product is despatched - they do not want to use shopify for payments.
Have you tired to do manual capture payments? Go to your shopify settings > payment providers > payment capture( all the way at the bottom) the payment is authorized but can capture at a later date. There is a timeframe that you can capture the payment before authorization period ends (7 days)
You can also custom manual payments. I'm not sure how it works, but is in the same page as above.
I hope this helps