I think that solved part of my problem, and I thank you very much for that!
However, I have a new problem. Here's what I did:
Changed the address in realmd to realmname.servegame.com (clicked the 'edit' pencil towards the bottom of the screen, and put in my realmname.servegame.com in the 'address' row, then saved)
Changed the 3 "localhosts" in both index.php and pomm_conf.php to my LAN / internet IP (the one I get what websites that "tell me my IP", NOT the realmname.servegame.com)
Then redid the "Setting up the client" part of the guide (under "actual realm" it says myrealmname.servegame.com, I pressed save, clear WDBs)
Changed my realmlist.wtf to "set realmlist myrealmname.servegame.com"
Now when I try to start the server, both 'Start Realm' and 'Start MangosDB' close right after I open them. The guide said to check realmd.log, and it says "ERROR:Cannot connect to database".
Are you noticing something i'm doing wrong in these steps? Hopefully helping me isn't too stressful. Your kindness is much appreciated.