Found it. :D "Choose script editor" under "Settings".
Also made my first scripting error discovery:
That bolded bit is the scrambled one in the picture I took, and I see now the reason for the scramble. I thought it was the question marks at first, but then I stumbled upon Groment City Museum's instance, which works fine. After more analysis, I figured out that \n seems to move on to the next line immediately while \l pauses and waits for the player to read, if I'm seeing this right. Therefore, all we need to do is change that to "\p????: Great news, let's go now!\lIt's time for the real LEADERS of" and it should be fine. Alternatively, since it's another person talking, another box can pop up with the other speech, separating it and removing the error that way; however, I see each box has its own code as well. I think the latter was in fact intended.
So, for whatever change gets made, the next question becomes how to save the script I'm looking to edit. I then need to plug in a trigger to cause the script to activate on a copy (not the original) of the ROM in order to test it (I don't need to retrigger the fires or sprites themselves, just the talking). If it works, then I change the other three in the original to match and move on after moving back to my saved state.