BYOD (accessing files) on a domain without joining?
Solution 1:
Why not take another route. Have them use VPN from their own devices. The proper way would be to allow them wirelessly on a guest network and have the vpn to access relevant sources. With this you can protect your network from untrusted devices. Trust me the last thing you want to do is run around and figure out who's laptop is generating suspicious traffic.
Once they are connected to the VPN they can map the network drives with their directory credentials.
Cheers, Dexter