Hi @michelandre
Good to see you figured it out… 
crontab is looking good.
Using local LDAP (either openldap or samba4AD) is a decision you will have to make. It has pro’s and con’s
pro: if you get a lot of users you do not have to create LDAP accounts for them with possibly (unwanted) permissions to other services on your server. Every user is only available for Moodle.
con: you might have double administration of users.
On my server I used Samba4 AD as accountprovider and configured Moodle to use that since I don’t have that many users and don’t think there will be a lot in the future neither.
Another hint if you want to create interactive material for Moodle: Howto install Xerte Online Toolkits