No. You can not share instances of a DevBox. You can share images of a dev box that would make getting up to speed quicker.

We recently ran into a similar issue where we wanted to create a VM and then allow one person to use it at the time and after creating the VM realized i couldn't share it :( '

See the associated link for more info: https://learn.microsoft.com/en-us/answers/questions/1336888/shared-devbox