The stock versions of Windows 10 does not run from USB. Linux and other OSes might but Windows requires the expensive Windows Enterprise and for Education systems. Read https://en.wikipedia.org/wiki/Windows_To_Go

As to the Macbook booting Windows from USB you have too many hurdles in my opinion here.

There is a trick I used long ago to get at a dead OS on just the pulled HDD. It's complicated and I only share to get you the method but do not offer more.

What did I do? I used a tool to convert the drive into a Virtual Box appliance. https://www.howtogeek.com/213145/how-to%C2%A0convert-a-physical-windows-or-linux-pc-to-a-virtual-machine/ gives you a look at ways to get this done. There are other issues such as Windows will balk at the hardware changes but it did allow us access to the point we could move the necessary information into a new Virtual Box instance.