Is there a pattern to the order of bosses in the Thunder Dragon's Boss Rush?
With many random number generators, the outcome can be manipulated because they run on an event counter rather thaan the system's internal clock (which is seperate from the one that tells the time).
It seems to me that this is one of those cases, thus resulting in the pseudo random numbers (meaning that they are not so random).
An infamous case of this type of thing is the GameBoy Advance game Golden Sun. You could manipulate the random number generator to make very rare drops a certainty in this game. It doesn't surprise me that Skyward Sword would do something like that, it is less resource intensive than true random numbers.
Basically, there isnt technically a pattern, but there might as well be.
What leads me to believe this is that one boss almost always got a specific boss in a specific order. In the Golden Sun example, in order to get the rare drop, you had to make the characters perform specific attacks on specific targets in a specific order to get the timing right. For example, character 1 attacks with fire, 2 attacks with ice and three attacks with lightning, but it has to be 3 that attacks first.
It almost ends up looking like its an if statement, which seems to be the case here, if first is tentalus, second has a 90% chance to be ghirahim. I dont think its exactly like that, but they are very similar.