Amazing news! Thank you ExO and EC team for all the hard work and time dedicated to continually improving both Cata and MoP! My kids and I look forward to getting both of these repacks running and enjoying all the fixes and features :D
To allow others to join, it is quite simple. You don't need to modify anything other than the realmlist table.
Open HeidiSQL, click the arrow beside the auth table, scroll down, find "realmlist". and click on it. To the right near the top, click on the Data tab.
ID = leave that be, I think...