Good day,
For this kind of situation, the VBox encryption should keep an adversary at least bussy for some time. Seems to go by proven standards, so should be fine, as long as you don’t rely on it alone.
Windows 10 seems to be supported now: https://veracrypt.codeplex.com/wikipage?title=Supported%20Systems%20for%20System%20Encryption
Never faced that. I’m also not sure wether LUKS on Windows will be faster than something specifically designed for Windows, you’d have to try that.
The thing is, while the person who designed LUKS tried to create a solution which would work independent of any encryption standard, LUKS in its original form is still heavily dependent on dm-crypt and its integration in the Linux kernel. So I can’t really tell you anything about the solutions for Windows and its security or stability. That’s why I’m always hesitant to recommend any solution which isn’t backed by a huge community.
Have a nice day,
Ego