Can you make a choir cassock that has all the bottoms on the outside but actually closes with a long zip?

House of Hansen can do custom work, so they can probably do that. I would call them about it. They are very helpful.

Thank you. That will make it so much easier to close or open. I will call within the next few days to ask a few more questions and to place my order.

Yes, they can do that. It's usually referred to as a false button front and can be done with any custom cassock prior to completion. The cost for adding a zipper onto a custom cassock order is $89.00. A zipper cannot be added to a cassock that has already been completed. (That would require all the button holes be sewn back together by hand, all the buttons be removed and then stitched on to the button holes themselves. The process of trying that is cost prohibitive. Also because button holes tend to stretch a bit over time its incredibly difficult to get them to look right.)