Linux – How to linux auto-create directories for a user at the first login

I don't know if you mean the CIFS FS will be served from linux or just mounted under linux on the clients.

However many non linux cifs implementations do not support stuff like symlinks and unix sockets so most window managers will die with a non linux cifs home dir.

Auth is no problem you can just use winbindd and you can as you say use pam_mount to actually mount the dirs on loging.

We have 6 labs of about 250 linux/windows dual boots. Their home dirs are mounted from a linux cifs share using AD logon scripts for windows and pam_mount and winbind under linux.

Try setting the uid= option when mounting hgfs - example on the web here. You probably want the uid set to whatever your uid in ubuntu is (id to find out).

Alternatively if you wanted every folder you made to be mode 777, that's umask. I'm unclear when you talk about the "vm not having access" - the VM has access, but not your account.