1) openssh supports this
2) openssh supports this
3) see pam_ldap/nss_ldap in ports
4) ack, SMB over the net - suggest VPN for such a devil
5) cron is your friend.
cron+find is your friend here. Example find command to delete old files
find /path/to/files -type f -mtime +30 -exec rm -f {} \;