I think that's normal - the network settings thing. I've had that happen with OS guests I was messing around with in GNS3, too.

Can you start *any* virtualbox VM in GNS3?

Is there any chance that the VM is running already? GNS3 8.3 doesn't do a very good job of actually shutting VMs down on windows IME. If you have virtualbox open, can you try again with the VM definitely in a shutdown state and then start it from GNS3?