netsinstall script was updated, and I think it will fix the issues you are reporting.
Original elastix rpm packages do 'odd' things, like resetting mysql password to eLaStIx.2oo7 in /etc/elastix.conf while mariadb has "no password" for root at installation time. So now the script installs mariadb, sets the root password to that old elastix default, then install elastix packages (with no auth errors on db). After installing elastix packages it resets the password back to blank, and finally executes elastix-firstboot so you can set the mysql root password and elastix admin passwords.