An issue that I am not sure is intentional is that it seems you cannot change from the base curse song if you do not have 5 hard bard levels. The wiki states to change songs and use the -song command, you need 5+ combined levels of bard and dirgesinger. I have found that even without 5 bard levels, so for example a 3 bard 5 dirge, can still use the -song command to pull up the song menu, but when you try to change your curse song you cannot change it from the first one.
After some testing I and others have found you can only change the songs once you have 5 BARD levels in total, not just combined 5 levels of Bard and Dirge. I believe this to be a bug because I can still use -cursesong 2 to change my curse song to Doomtempest Dirge which is supposed to do bonus electric damage. And when I do this and cast curse song it even says i am "Preforming" it, but then the following damage doesn't seem to be what you would expect, instead it seems like it is doing the base curse song damage. i have some attached screenshots below that are all on a 4 bard/10 dirge/16 assassin character on the PGCC showing the situation that I have mentioned above.
Would appreciate knowing whether or not this is intended but it doesn't seem like it.
In the second screenshot above that is on the menu that explains the -song and -cursesong command, showing I have venomous verse selected, and the third screenshot shows I still have Aria selected even though I used that menu and -cursesong 4 to try and change it. This is another reason I believe this to be a bug.