CthuluIsSpy: I noticed that in most campaign levels the AI doesn't seem to build new units.
This makes some missions, such as the Raid on Bespin, really easy as all you have to do is survive the initial onslaught and you can just dismantle the enemy bases.
Is that normal? In some missions the AI does send raids but I'm not sure if they are actually being recruited or if they are event spawns.
I tried just running the original SWBG executable but there doesn't seem to be music? Is there a way to fix that?
May as well try to reply even if your post is a bit on the older side.
The Clone Campaigns expansion introduced a bug that broke AI scripts in the original Galactic Battlegrounds campaigns. The result is that the AI opponents in the GB campaigns are borked and often don't react at all to your actions and attacks, making most missions trivially easy as a result. The two CC campaigns are not affected, so it should be possible to check this by trying to run one of the CC campaigns and see if the AI fares better there.
To this day the only way I am aware of that lets you fix the problem is the Expanding Fronts mod, which fixes it from version 1.5.3 onwards. Unfortunately this comes with the rest of the mod as well: of course, the campaigns themselves are unaffected by all the new content, but the mod does edit the campaign maps AFAIK with some minor changes. If your goal is to play the game as originally intended by Ensemble/Lucasarts, but with the bug fixed, there's no way to do it (the All-In-One patch does not fix it last I checked).