I got the balloons to spawn on one of like 10 different worlds I made, and Victor didn't have balloons in his world.

I separated the balloons from the armor stand and added another initialization step to the initialization process. When it still didn't work, I tried to put it in the quest book, but that didn't work either- probably because 1 second after the quest book was avialable was not enough time for the player to be transported.

I started realizing that even though the balloon structure block wasn't being placed, I could place blocks near the player, and I began to realize it might be a chunk loading issue, where the player was in the right place but the chunks around the chunk the player was on had not loaded.

Eventually I discovered and used a way to test if a chunk was loaded, which was to execute if a block was 'readable'. I realized I could reuse this and test for the structure block's existence before changing any tags, printing any messages to the screen, or even putting down the redstone block. Now the initialization code runs multiple times until it finally detects the structure block was placed, ensuring that the structure block IS placed, as a result.

It now consistently spawns balloons.