Question about Quantity

Hello, I searched and found the answer to one of my two questions.

The shopping cart is being set up for a company that doesn't really have "stock"...it's more of, someone places the order, they build it, they ship it.

so when they add a product, the quantity is most likely going to stay at 0.

So, when it shows up in the cart, it shows up as "out of stock" or "sold out".

How can I make it so that even if it's at 0, then they can still add it to their cart and check out?

Thanks!

Admin>Configuration>Stock>Show Sold Out Image in place of Add to Cart (change to 0, Off).

Following on from that, it says X units in stock. I want to hide that (same situation as above so can be built). I've searched but can't figure out how to hide it.

Admin>Config>Product Listing>Display Product Quantity -- set to 0